I know that the holiday pay and maternity leave thing has been done to death a bit, but this is a strange situation.
A staff member who I manage was suspended for a substantial period of time, reinstated, came back to work for 1 week, then went on sick leave long term (6 months), then came back to work for 1 week, then went on maternity leave. Unfortunately her DC died shortly after birth. 
She remained on maternity leave for the full 12 month period, during which time she became pregnant again. At the end of her 1st lot of maternity leave came back to work for 1 week, then went back on 2nd lot of maternity leave, gave birth and fingers crossed all seems well this time around. 
My question is, she had now accrued 2 years worth of holiday entitlement, which she has had no opportunity to take. This amounts to 60 days holiday. We are now at the point of the new holiday year, and I am not sure whether I should carry the whole lot over, add it to this years holiday giving a total of 90 days for this year, or what. BTW she is not due back from this lot of ML until November if she takes the full allocation.
HR have been rubbish, they are unsure what the position is WRT back-to-back ML despite me hassling them for the last month, but I need to get this sorted this week asap!