The dive shop is Remar in Caerphilly, tel no. is 029 20860416, not sure if the price was a special for me, as i do a fair bit of filling there, and get on with the owner quite well.
The Bridgend shop with the 232 bar mains powered compressors is Keen Guns, but i don't have a number for them.
Hpac gave me the price for a 300 bar mains powered compressor, which i'm pretty sure was £1300.
Yes, you would need regular servicing, and i would have thought that it would be pretty expensive, ideal for a team, a bit expensive for a single person.
Team Demonic, for ease of use and portability, most paitballers use a dive tank, so this is probably the best advice we can give, but whatever suits your needs will be better for you.
Enjoy your paintball, but respect the high pressures that your using.