We did have a glossy magazine called "Western Rider UK".  I paid for a years subscription and heard no more!

many of the regional publications feature western; my husband has been writing a western page in the Essex Rider for around 4 years now, and I've noticed similar pages in other regions' magazines. Horse & Rider is my personal favourite monthly publication (the American one) and it can be subscribed to and sent over here.
Don't think that the UK market is big enough at this stage for a professionally produced, marketed and readily available UK based publication though.

When I have talked to 'horsey' friends in England their idea is you must also like line dancing and country music to ride western...

oh Isobelj, yes you are right! whenever I talk to someone horsey (or even non horsey) and they don't know anything about western riding they always assume we like 'country and western' and dressing up!
The funny thing is, once we started getting into western riding, visiting USA etc, we found ourselves humming along - now I really love country music!! How sad am I!