You can print all of this on your printer. I use to run a 60" for a printing company. As far as your distributer goes,being im from the US, you may have to be a bit more choosier. If you are running a roll fed printer and your prints are coming out washed out then you are going to want to color profile your printer for the media that you are using. We ended up having a tech come in and run calibrations once a month on our equipment, but you can do a pretty good job by yourself.
Gretag macbeth, and EyeOne both make color profiling systems so that you can get your color output just right.
As far as hp material, Im not too wild on it. Ive used lexJet in the past and used them for around 3 years. I'm sure the UK has some good suppliers that copy other medias.
Here are some back lit options for your printer. Not all come in 24, but if you order a 48" they will cut it in half for you. Backlit material prints just like standard media, but you backprint it, and set your printer to reverse the image.
http://www.lexjet.com/lexjet/dept.asp?dept%5Fid=13140Here are some self adhesive medias.
http://www.lexjet.com/lexjet/dept.asp?dept%5Fid=13144All in all you have a awesome setup.
If you call ( ask for Angela Albritton) she's a rep I used and although she doesn't cover your area, she is one of the most helpful people I've ever dealt with in sales.