Just got back from Benidorm and my was it hot!!
Went to Mundimar and yes you can have your photo taken with the dolphins, collect a voucher from the assitant to the right of the pool and she will send you down to and area of shallow water where you stand/crouch next to the dolphin. Not allowed to touch it though!
The sincronised (spelling!) swimmers in with the dophins are brilliant though, first time l have seen them..smashing.
You can also get your photo taken with the seal before the show starts so arrive early the queue was massive.
You can get vouchers from the man on the bike to give you 3 euros off. We paid 31 euros per adult for joint tickets for mumdamar and aqualandia.
We also managed to get some vouchers for 10 euros off terra mitica which was from the van on the front. Terra mitica closed at 10pm. We went for the evening 5 -10pm a bit cooler and not so crowded.
Hope that helps