I've just received a letter from my Employer regarding my performance related bonus payment. They've confirmed what percentage i've been awarded but have then gone on to say that the payment has been reduced because i was on maternity leave for more than 9 weeks of the awarding period (April '09 to April '10). They've basically paid me half of what i was expecting.
My performance review was done mid April at which point my Manager confirmed what he had scored me as, so i had a rough idea of what payment to expect. At no point was i told that my bonus would be pro rata due to my maternity leave so it was a bit of a surprise to recieve this letter.
Are they allowed to do this? Any advice would be greatly appreciated. Many thanks.