In a nutshell, the personnel dept said I might have to pay back my maternity pay if I chose not to return to work for at least three months. I am only receiving SMP and unless things have changed, I thought you didn't have to repay this. Everything I've found online suggests so anyway.
just so you can double check directgov says that smp is
for the first six weeks at 90 per cent of your average gross weekly earnings with no upper limit for the remaining 33 weeks at the lower of either the standard rate of £128.73, or 90 per cent of your average gross weekly earnings