Holy thread revival and all that.
I was the OP and the issue is sorted and I think it's always good when you're searching old threads for solutions that people have taken the time to update when they have cured their issue.
It's taken a while but I just had some (a lot!) of work done up at Autolusso Penrith and asked Dan to see if he could sort my brakes as none of the easy fixes mentioned earlier in the thread have worked over the intervening period.
Long story short, the root of the problem was twofold:
1) The pads were dragging a little due to the calipers needing a refurb causing the brakes to get warm (but not enough to seize) and under-perform. This was also causing occasional pad transfer and therefore vibration
2) One of the pads on the piston side of one of the calipers was at an angle so only part of the pad was in contact with the disc, again causing them to under-perform and also causing the long pedal.
A bit of fettling and a set of Performance Friction pads later and they are now superb, exactly how I expected them to be when I first bought the car. I know the PF pads will have made a difference over standard anyway but Dan assures me that if they'd just put a set of standard pads on the difference would still have been night and day.
I think the message is, as a lot of guys on here have previously said, with the Brembos, if the calipers are in good order then the standard setup should be pretty decent. Unfortunately for me, long term, I need to send my calipers off but that'll have to wait until my wallet has recovered
Will also say Dan is a top bloke and great to deal with, although he seems to have taken lessons from Ned in persuading you to spend your cash