Yes, I agree Chris.
The enclosure DESIGN is outdated......
Since Twycross are now advertising themselves as a 'World Primate Centre' I would suggest that they need to live up to that name with the design of their enclosure.
I am not criticising their husbandry or quality of care as they have very good records in this regard, and possibly much of my issue is to do with the way they look rather than anything else, but many of the enclosures just have that 1960/70s feel.
While the orang, bonobo & gorilla enclosures are not the worst I have seen, the chimp block reminds me of a prison building. Given the spacious enclosures for chimps at many smaller UK zoos, it dosn't seem acceptable to me to keep chimps in this way in the UK in this day and age.