If the MOD/RN/RAF are going for the -B then wasn't the planning originally for them to be based at Lossie (partly due to noise) with all the GR4s being moved South and then slowly withdraw from Service at Marham? Were the infrastructure works halted there when the decision was "temporarily changed" to the -C? Unless the RAF get -C as a replacement for the GR4 I can't see RAF Norfolk surviving (as an operational airfield) past the GR4.
Besides, not sure the 'locals' will be too happy with the -B at RAF Norfolk (but at least they will have no shortage of fingers to stick in their ears
)