ps2 to vga working using just a component cable and rgb to vga adapter
Finally got this working using a component cable from ps2 connected to a rgb to vga cable, as many suggested had to use gsm mode selector. For some reason (possibly because I have a psone analogue controller plugged in, which some games eg driver dont like/recognise) I had the same problem as some where pressing triangle to select a mode did nothing, after going to sksapps > ps2 apps > misc apps (sorry new member so cant post link MOD if you would be so kind?) and downloading all 6 versions of gsm selector I managed to get it working with v0.23e which uses a different button configuration for the various settings e.g. vga is < + X so I suggest if its not working with a version of gsm try them all as this was my fourth go. good luck!
BTW the whole lot including audio adapter for the speaker jack only cost £6 from amazon and poundland so well worth doing.