Yes, I bought a tax disc for my Carry, too, on Thursday, the first day when it is permitted to buy one starting 1st May (although the vehicle must not be used on the public roads until 1st May - the cameras may get you if you use it before then).
I paid £115.50 for a six-months disc - as it will be on SORN again from 31 Oct, a six-months payment, although proportionately dearer, suits my situation. I've found that if I buy a twelve-months disc and then apply for a refund, it is a lot of fuss and it takes a further 2½ months and several reminders to DVLA to receive the money anyway. I suspect DVLA hopes you will forget about it and so they can keep the money. So I don't mind paying the 10% premium.
I'm going to Ireland for a week in my campervan on Wednesday, via Holyhead/Dublin.
Sqn Ldr Alan Birt
Owner of two Suzukis: a Wagon R+
 and a Carry  campervan in
England (plus a Nissan Vanette 
campervan in New Zealand)