Just spoken to the hotel via email.
I had complained as i'd found it difficult to book anything via their system, and that time was running out for me.
The voucher was due to expire on the 4.April, but he would be willing to extend it to be used on the 19/20 April. That is the Tuesday and Wednesday after Easter I believe, could extend your Easter break a little longer with some wellness
Also he put in the mail the 24.April which is a Sunday, I'm waiting for confirmation this means Sun and Mon 24/25 and will post here as soon as I get that info.
Really would be a shame to waste this offer.
Please PM me your mail address and I'll scan and mail you the voucher for inspection - No doubts that it is transferrable as the names are not on the voucher.