Answer by Helen Climance

Some employees are fortunate to have a contract of employment that entitles them to maternity pay in excess of the statutory minimum. This can sometimes be as much as full pay for the full term of the maternity leave period. The problem is that it is normal practice for these schemes to require the employee to return to work for a period of time following maternity leave. If the employee does not return, the employer is entitled to ask for the additional sums to be re-paid.
In a situation where you decide not to (or are unable to) return to work following maternity leave, any holiday that you have accrued during maternity leave would normally be paid to you in a lump sum in your final wages. 
In this particular situation, you are entitled to payment of your holiday pay, but your company is likely to have authority in your contract of employment to deduct from your wages any sums that are due to them (the excess maternity pay). Therefore, it sounds as if what is being proposed is fair. I’m more than happy for you to telephone me if you need any further advice and Lemon&Co offers assistance on a no win no fee basis.
This gives a general overview only, based on the information available at the time of writing. It cannot be relied upon in any particular case. Specific legal advice must always be considered to include consideration as to whether the legal position contained has changed since publication. For further information and advice, please contact Lemon&Co Solicitors on 01793 527141 or visit their website: www.lemon-co.co.uk.