and here is the final answer......as copied from the email!
The question of annual leave entitlement during maternity leave is (as you now know!) a complicated one - the answer depends on whether you take ordinary maternity leave only, or ordinary plus additional maternity leave.
As you already know, whilst on ordinary maternity leave ("OML") (ie the first 26 weeks), you have the statutory right to continue to benefit from all of your existing contractual rights other than pay. This means that you will continue to accrue annual leave and on your return to work you will have accrued the same number of days' leave as you would have had if you had not been on OML.
During additional maternity leave ("AML") (ie a further 26 weeks leave for women with sufficient continuous service), the position is different - only certain contractual rights will continue to apply (unless otherwise agreed). The contractual right to accrue holiday entitlement is not one of those that will continue to apply during AML under the Maternity Regulations. Consequently, you would not continue to accrue holidays during AML unless otherwise agreed with your employer.
However, recent case law suggests that you might still accrue your statutory holiday entitlement under the Working Time Regulations (ie 4 weeks per holiday year, inclusive of bank holidays). This is quite a controversial view, though, and is currently the subject of argument at the Court of Appeal.
However, you would not have the right:
unless your contract of employment specifically allows it (which, seeing as you're a teacher, I doubt!). Therefore, if your maternity leave spans the end of a holiday year and the beginning of a new one, any days leave that accrue in the earlier holiday year would normally lapse as you moved into the next holiday year.
Any holiday which does accrue during maternity leave would have to be taken in accordance with your employer's usual rules on holidays (which presumably for a teacher would be that leave can only be taken in school holidays).