Having been to Howletts today, I can confirm that:
a) The red-bellied lemurs are already onshow
b) They have taken the place of the black-and-white ruffed lemurs in the walkthrough enclosure. No word, however, on whether Howletts have merely moved the ruffed lemurs offshow or have gone out of the species.
All in all, I really enjoyed Howletts - definitely one I would recommend to everyone who hasn't already been. And amazingly enough, we managed to see almost everything which was on-show - even the various notoriously elusive species of cats! The only no-show was the Heck's Macaque - I have no idea whether they were being kept offshow or whether I was just unlucky, but judging by how active and visible their Sulawesi cousins were, I wouldn't be surprised if it was the latter.
As regards a recent discussion about the Lynx at Howletts, they were identified by the guidebook as being Northern Lynx - Lynx lynx lynx, in other words. Judging by the morphology, I suspect this to be accurate.
My only complaint, really, was the severely out-of-date and sometimes mispelt signage on enclosures! I am reasonably sure it has been a long time since ocelots, servals, lynx, fishing cats and pallas cats were all classed under Felis, and I am certain that the African wildcat has never been classed as Felis
syvelstris 

The guidebook got all of the aforementioned species names right, though.