I do know that you would struggle to get on the Intergrated courses, as they ask for a minimum of a couple of A-level passes. Going modular I can't forsee a problem, although not having A-levels may count against you when getting your first job.
There was a very similar thread raised recently but can't seem to find it
edit: found it... http://www.pprune.org/forums/showthread.php?t=321558&highlight=gcse