There will be quite a lot of £25 tickets. The £35 is a tiny part of the stadium.
I didn't mention in my op that I'm taking someone along with poor mobility so I'm trying to avoid the stairs. Typical that the person who's coming along can gets discounts for age/disability while I have to pay extra for taking them.
Having checked you'll probably find seats for around £27 Kampala if you don't mind the stairs and can remove your legs when seated.