Hello LM
I'm still working on sites as a decorator and been asking the same questions. Dan is right your better writing to the developers or the main contractors head office to get on a tender list when your on the list which may take some time I believe they will send you details to price on.
Like dan said it is a case of not what you know, but some agents have told me that for smaller jobs which are a good size to you and me they may go for the cheaper tender which rules out the firms with the big overheads.
I'd give them a go it can't hurt to try and if you've got time to wait it might be worthwhile in the end.
But the
CSCS Card is an important factor though.
Hope this helps good luck.
Rich