Apologies, I have double posted this as posted in employment and then thought it might be better off here? 
To be honest from the beginning, this issue doesn't concern me, I'm finshed expanding my family but have a friend/ colleague in this position now and an trying to gather information on her behalf.
I work in an NHS Emergency department as a nurse and have a friend who has been working there a while as a band 5 nurse. We're having real problems at the moment recruiting and retaining staff at band 5 level so they have introduced a kind of bonus system whereby once you have worked in the unit for 6 months you receive £500, then £500 at 12 months and finally £1000 at 18 months employment from the beginning of July this year (so anyone who was employed at the beginning of July starts from day 1 at that point no matter how long they have been employed for).
It states in the paperwork that if you're off on long term sick leave for over 1 month that the bonus will be pushed back till you've actually worked 6/12/18 months and ditto for maternity leave. So, if for example you were due to go on maternity leave in feb 2014 you would get your initial 6 month bonus in your Jan pay, but then if you took a year off you wouldn't receive your 12 month bonus until August 2015. And it would be impossible to receive your 18 month bonus as the 'scheme' ends in December 2015.
Does this sound legal? It sounds on slightly dodgy ground to me as the mat page bit only applies to women? I'd be grateful of any advice I could pass onto my friend, TIA.