I live in Italy, where the analog TV used PAL B/G systems (B for VHF channels and G for UHF ones) and I was able to use an Atari 2600 from UK (PAL-I, UHF only) on my TV by simply adjusting the audio frequency (there's a variable inductor for that on the console), actually converting it into a PAL-G console.
Since a PAL B Atari 2600 or 7800 outputs on VHF channels, unless your TV can receive VHF (according to
this wikipedia page it was discontinued in UK in 1985) you can't do the same.
I think your only option is then to A/V mod the console (the only differences between PAL-B and PAL-I are in RF frequencies, they are the same in composite or s-video). I used the
"easier 7800 composite mod" on my PAL B 7800 and I'm very happy with it (
Here I posted where to find the signals on the PAL-B board) Anyway, I always play it on a CRT TV. If you plan to connect it to a modern LCD, you should probably try some more advanced mod whith S-video output to get better results.
Edited by alex_79, Thu Sep 22, 2011 3:45 PM.