Fintastic -
BEOB has a point - if you can sort it on the phone do so. If you do write to the pensions people, don't expect a speedy reply. In fact don't expect any reply until you have phone JPAC twice to complain some 6 months after your original letter.
And then when you do get a reply, sit down, take a deep breath, remember that if you pay peanuts you get monkeys and prepare to draft another letter or make another call complaining that they didn't actually answer any of your questions from your original letter.
Slightly flippant maybe, but sums up my recent dealings with the pensions people. The ony time I spoke to them a couple of years back when they moved me across to the new scheme, I managed to get is sorted in 5 minutes. Phone is definitely the way ahead if you can get anyone at JPAC to give you a number or put you through.