Mono,
As the others say I don't think you need PPR. I remember going in there a few years ago with a friend, and he didn't call anybody for PPR before hand. I think that its now owned (or at least operated) by the people who import Rotax engines and the EV97 Eurostar, so you could try the contact numbers on the
SkyDrive website.
I pretty sure that the information in Lockyears is out of date, as they advocate contacting Heyford Radar for a flight information service!! Unfortunately I don't keep my (uptodate) flight guide at work otherwise I'd PM you the contact info from it.
Brooklands