Interesting, thanks for replies so far.
Have attempted to speak to a member of Maths Dept or someone in 6th form at current school, none available as "they have a lot of cover teachers in at the moment" so then rang one of the other consortium schools. Immediately put through to very knowlegeable person in 6th form, who gave me all the info I need at this stage and was very keen to furnish me with more. Amazing that I get more joy from a school he doesn't go to than the one he does - but this is par for the course, has been increasingly the case over the past year or so.
At the other school, in order to do Physics at 'A' level, they will accept C's in physics and maths GCSE. I suspect the B's being asked for at current school are due to the fact it is a science college - other school is not.
Also have concerns over the Geog. dept here - have been to-ing and fro-ing for most of Yr11 over whether he will be sitting foundation or higher. Along with 2 other pupils, he was given the wrong mock gcse paper to sit, which took a lot of fudging over and correcting. He recently achieved an A* in a test, and has been consistently achieving b's, with an A for his coursework, so we will see.
Thinking laterally, I am wondering whether it would be possible to register him at the other school for Yrs 12 and 13, enabling him to study Physics there without the need to resit the Maths - a C would be sufficient for his chosen career (forces) and preferably Geography there, then maybe the other two courses at current school on the consortium arrangement if absolutely necessary.
In all honesty I am losing what faith I had in current school due to the lack of/lateness of/innacuracy of communication - we had this with DS2's GCSE's a couple of months ago, and have been uncomfortable from the off with him staying on here to be honest, but he insisted.
We are definitely going to request a meeting with the Maths teacher, preferably his Mentor as well on Monday, with DS present, and I would like to go and have a look around the other school with him as well. I think he is starting to realise that he does have other options (at least I hope he does and it's not too late)