I'm with Alan for his first paragraph - you should never, ever cut into a raft foundation. It's been made the size it is for a purpose and breaking into it is likely to end in tears, as you risk exposing steel rebar, or even inducing a crack. Leave it alone.
And I'm with Alan for the first part of his second paragraph, in sharing a dislike for PIC - as I say somewhere on the main site, I get more complaints about PIC than all the other forms of paving combined, and that includes Tinker-laid tarmac! When it's done properly, it can be almost attrcative, but so much of it is laid by incompetent buffons who make ludicrous and unsubstantiated claims about the stuff, and then wonder why their clients end up disappointed.
However, Alan loses me completely towards the end of his post - I've no idea what he's on about, and I'll just have to put it down to an adverse reaction to the footy result last night.
Care to shed any light on the thought processes behind your troubled stream of consciousness, Alan?
Anyway, back to the problem: going off what you've told us, Lizzy, I'd suggest using a gravel as a surface dressing over the shallow raft. You could use a loose dressing, one of the self-binding gravels, or if you're looking for summat with a bit of class and style, one of the resin products.
I'd be reluctant to cast PIC over the raft, but, if that's what you really want, then I'd insist on there being a break layer between raft and PIC, say a 25-50mm layer of sand or similar, so that, when you come to realise what a disastrous mistake was the PIC, breaking it out with a jack-hammer isn't likely to damage the raft.