I don't know how you access upcoming releases at Amazon yourself, or if you just look through the whole list, but you can see what's coming up quite easily. This is what I do:
Go to Amazon UK. Mouse over Music, DVD & Games (second down on the menu on the left). Click on Blu-ray (4th down).
If you scroll to the bottom of that page you'll find links to a list of the upcoming titles for the next 9 weeks, which you can access individually, with the 9th week also showing what is to be released beyond that.
So, for example, today you'll find lists for releases on the w/c 19th Jan, 26th Jan, 2nd Feb, 9th Feb, 16th Feb, 23rd Feb, 2nd Mar, 9th Mar, and 16th Mar & Beyond.
There are generally only around 1 or 2 pages of releases for each week (with 12 on each page).
It's not the most user-friendly way to browse, but I generally check in every week or two to see if anything new has been added.
What with that and the news we get here, I'm usually well up to date with what's going on. I agree though, it's a shame we don't have a UK version of High Def Digest.
Perhaps it's a resource this site could provide? It'd certainly be a good advert, as you'd get plenty of people tuning in for that, then joining the forums, too.