I agree Liam, but it isn't just the 'Snap on' kit, one of the lads did a code read on a Vectra last week with the Bosch KTS, one of the code descriptions was
P1191 - undocumented code.

So I put the Vauxcom on, - same code but a good description of the FRP sensor fault.

Live data then proved that it had fuel pressure way above the desired pressure.

Just goes to show it's always worth double checking, especially if it's not dealer kit.

Nick