Cow Roast Lock to Dunstable Downs

We had to start off by driving over from Norfolk, but by 10am we had left one car in the National Trust car park on the Dunstable Downs (TL00819) and driven together in the other car to the start of today's walk, back in the large lay-by on the A4251 at SP964097, just to the north of Dudswell. From here we retraced last week's steps back to the Grand Union Canal at Dudswell Lock (no 38). We hadn't expected much activity on the canal at this time of day, so we were quite surprised to see that a boat had recently passed through the lock. The trouble was that the next section of the canal was rather low on water and the boat that had just gone through the lock was grounded. It was a hire boat, but the people in it seemed to know what they were doing (perhaps they give you instructions?) and had opened the next lock up, to get more water, which meant that for a while as we continued to walk along the canal, the water was flowing "downstream" as if it were a river. Looking at the locks in more detail, we realised that this must be quite a common occurrence for the first boat to go through the lock in the morning; the two Dudswell locks are old and leaky, whilst the Cow Roast Lock is new and pretty watertight, meaning that the water in the intermediate two sections will eventually drain away. Anyway, we got to the Cow Roast Lock, where there was a heron for company, and rejoined the Chiltern Way.

From Cow Roast we climbed slightly and crossed the main West Coast Railway line on a bridge, then skirted Norcott Hill Farm and continued to climb diagonally across a field. As we climbed, there were occasional views back to passing trains, but they were usually in a cutting so we could often hear but not see them. More clearly in sight was a elegant bridge where the Ridgeway trail crosses the A41 near Tring. We'd crossed this bridge on a wet morning in June 2013, on our full day of walking on the Ridgeway but it is only when viewed from a distance that you appreciate how much of a landmark it is; I was in London twice for work in the week following today's walk and on both occasions I glanced up from the train and noticed the bridge.

We entered woodland and turned right onto a track. We climbed Tom's Hill and after passing some impressive looking buildings which were hidden away behind a wall, we reached a sign which informed us that at least one of the buildings was Tom's Hill House (though the sign doesn't have an apostrophe!).. After a further section in lovely woodland, we reached a road, right on a sharp bend (apparently to get round the feature known as Gryme's Dell) with cyclists whizzing down the hill. We would cross the road again a short distance further on, but it would be far too simple just to walk on the road which was relatively level in this stretch; instead we headed off on a path downhill to the edge of Aldbury (which looks to be a pretty village) then uphill again back to the road.

As we crossed the road, a cyclist who was puffing and panting his way up the hill told us the rather impolite name that cyclists use for Tom's Hill. Soon afterwards we too were muttering, as the signposting, which had been good, disappeared completely at a junction, leaving us guessing. More by good luck than good judgement, we picked the correct route.

We were soon walking across the National Trust's Ashridge Estate, quite busy with walkers, runner and cyclists, but very attractive. We crossed a road and a small car park, and Richard realised that - according to the map - we didn't want the straight ahead path. We took a delightful more minor path, stopping to talk to a dog-walker, who clearly felt that we were walking a very long way and therefore expert walkers! However a short distance further on, we realised that this route was not going to get us where we wanted to be - so much for experts! - so we waited until the dog-walker was in his car then crept back to the more major route. We then took a sharp left hand turning (which was signposted) and managed to correctly navigate the route despite some more less-than-clear signposting, with one example being a signpost pointing straight ahead but positioned down a path to the right.

Since our climb above Aldbury we'd stayed pretty much on the level, but after crossing the wheat field, the route descended by about 60 metres to the A4146, passing from Hertfordshire to Bedfordshire just before the road, then back up the other side, along the side of another crop field. We followed the edge of Ravensdell Wood then cut across fields to Studham. We didn't go properly into the village, but rather wiggled our way around to the west of it then headed north on a track along the end of Church Grove. It was only when curiosity got the better of me that I left the track and looked across a field of cows and noticed Studham Church in the distance.

We continued along field boundaries towards Whipsnade, obviously just beneath the flight path for planes landing at Luton Airport; planes were coming overhead regularly and I eventually managed to photograph one. We joined the Icknield Way Path on the edge of Whipsnade Zoo. We were last here (meeting a woman and her dalmatian puppy) on a misty morning in November 2011. The long grass the other side of the fence was initially a disappointment, but then we started to see wallabies and I eventually managed a half decent photo (note to self; don't worry about trying to get my camera lens through the chain-link fencing, just ignore it!).

We turned left onto Studham Lane which brought us down to Whipsnade Village at the church. The church looks relatively modern, though appearances can be deceptive, as parts of it date from 1480. We crossed the B4540 (to get to Old Hunters Lodge, where stayed last time, you'd turn right here) and took a path from the Green which went past the Whipsnade Tree Cathedral. We popped in for a quick visit, but concluded it was more atmospheric in the half light of a November afternoon i.e. last time we were here.

We continued to head north and soon reached the Chiltern Hills Escarpment at Dunstable Downs, busy with picnicking families and kite-flyers etc. We stopped for an ice-cream before heading back to collect the other car, and so to our flat in Simpson.

Following leg