Thanks ladies. I did a bit of 'googling' and found this on the direct.gov website which is exactly what I was after! I needed it in black & white that I can use all my holiday up for that holiday year if it goes over two holiday years before maternity. Ill then get everything accrued in the 2nd holiday year at the other end! Woo hoo....14.5 weeks left at work!!
"You can add holiday to the beginning or end of your Statutory Maternity Leave. You may not be able to carry over untaken holiday entitlement if your Statutory Maternity Leave goes over two holiday years. It is often best to take this at the beginning of your Statutory Maternity Leave"
(oh and I dont get anything enhanced - just the bog standard SMP so I dont have that to worry about!)