Here are some other opportunities for undergraduates to do research in maths:
Summer Research Programme for Undergraduates from Underrepresented Groups (based at the University of Warwick).
Polymath Junior is an online research programme which "aims to provide research opportunities to "every undergraduate who wishes to explore advanced mathematics".
The University of Edinburgh maintains a list of programmes.
PiForum is a yearly conference providing networking opportunities and support for women and underrepresented genders at undergraduate, Masters and PhD level as part of the Piscopia Initiative to tackle the participation crisis in mathematical research.Â