Found that this offer was stil available on the day when other cheap options like the advance booking for £33 or the groupon 29.50 were no longer available.
Don't think so as you only buy through the link on the page which doesn't give you that option
Can you use the vouchers to pay the extra £20 that is costs 'annual' pass holders?
Have to agree with other comments. I went on Tuesday and as a Merlin annual pass holder this was our worst visit. We arrived early as we weren't interested in the mazes but spent all day queuing.
I went last Friday about 3pm til close and we managed about 7 or 8 rides and 3 mazes. Could have done more but stupidly wasted an hour trying to get on the Derren Brown Ghost Train... so underwhelming don’t bother with it and prone to technical issues/breaking down.