vicky, don't try with free unlocking software which may lead to have a dead Torch. where do you live? if in delhi, just go to karol bagh and get your BB unlocked with < 1000 bucks. there are two types of unlocking process
afaik, i. inserting a chip just under the sim holder and ii. unlocking thru resetting BB with a code. i have unlocked my BB in Noida (not able to recall the name, he is a distributor of BB) which costs me 1500 bucks, but also got a 6 months replacement warranty.
or, you may call to your existing service provider (UK) asking for the unlock code as you have been moved in to india and will use your BB here.