There is no unique "UK authoring process." I have probably 40 UK BDs, 20 Canadian BDs, 10 Japanese BDs, and a handful of others from France, Germany, Korea, and Italy - I've never run into one with any playback trouble. And while I don't have the UK Bourne Trilogy myself (got the US version when it was first released), it is one of the most frequently imported titles because of its cheap cost, and you are the first one to report any problems with it from the various websites I frequent (here, hdd, bd.com, htf, etc.).
I would try wiping the discs with a lintfree cloth to clear any possible residue, and I'd make sure my firmware was up to date. Hopefully one of those things will fix your problem. I guess it is possible that whatever player you are using truly has an unresolved incompatibility with these titles, but everything I have ever seen on this subject points otherwise (and like I said, I'm a frequent importer).