Have you done the sums on agricultural profitability if you strip £100/acre out of the farm equations?

Big difference between East and West. In East big farmers can expect to make 100k/yr of which about 10% from subsidies. In West with family farmers, lucky to get 20k, at least 15k of that coming from subsidies (ie more land but poorer quality)

Have you compared the landowner farmer vs the tenant ?

Not much, but do know that tenant farmers often annoyed and powerless to stop landowners taking big chunk..see Tenant Farmers Association

Variations according to crops/livestock? Seasonal variations?

Horticulture never really had subsidies, but got these 1st Single Farm Payment in early 2000s. But get proportionally less as use less land. Yet this small subsidy was enough for Labour gov stopping funding of International Vegetable Research station Wellesbourne - saying they now had subsidies for first time.

Can't think there would be season variations

Do you really think the recipients "do nothing"?

Properly I should always say 'for not doing anything in particular', but I want to get point across, they do not have to do anything, which means they can do nothing - and some do. The Estates Manager for Duke of Westminster picked me up on this exact point saying he was disappointed in my start, and that on their Cheshire Estate they had a large herd of cows giving employment to many, which I should be pleased about. I was but replied that he wasn't doing anything like that on the Estate here in Bowland Fells, as all they did was shoot grouse - which to me counts as nothing. I had a big row over just this with Lord Curry (he of famous Curry Report in early 2000s), saying 'grouse are not what I'd call sustainable food'. I am not alone thinking this - even the Spectator describes the estates as "economic deserts without parallel. " I offered the Estate manager chance of continuing debate either at his farm or the local hostelry on the Duchy of Lancaster's Estate (next to the Duke's) ..never heard back.

Clearly some of the subsidies are absolutely necessary for many farmers round here, some of whom are pondering going to food banks. But for all those, there is an awful lot of money leaked to do nothing. And that mrans it doesnt get back into the local economy

In my book Bittersweet Brexit, I argue that these subsidies should go to workers, when the money xoulsdb directed to food and farming we want, and it would go back into rural economies. Because there is no actual targets, much goes unaccounted for in terms of productivity - which is where we started.