Couple of options for you:
Scott Leathers are made in the UK, they do have a made-to-measure service but they can also 'tweak' any of their own, off-the-peg suits to get a better fit. I've dealt with them in the past and found them very helpful. Here's a link:
http://www.scottleathers.co.uk/default.asp
Another option is to find something you like that fits you in length, then have it altered by a company like The Leather Workshop http://www.leather-workshop.co.uk/ . These people were recommended to me by the fantastic people at Scrubbers Leathers http://www.scrubbersleathers.co.uk/ who did a fantastic job of cleaning all the UK Coach and Hire leathers this year, not only making them look almost like new, but also made them soft and supple again, can't recomment them highly enough!
Let us know how you get on,
Spidey