This will not be easy to fix, you are using a set based on PAL B/G (north europe) on PAL I (Uk). The sound carrier of pal I is offset +6mhz and pal BG is +5.5 mhz. You would need a new tuner and IF block - and a few other modifications to the set -not cost effective.
Get another (UK) set, or buy a UK vcr (an old one with broken cassette deck will do) - connect it using SCART lead to TV AV input, then use the tuner of the VCR to receive programmes.
Ben, November 2004