Thanks every body for your help. I signed up for an 18 months contract with BT, though I might have to move again after 12 months. If I leave in the minimum term contract period, I have to pay £7.50 per month for the outstanding period, which amounts to £45 which is still not bad as compared to paying £122 as installation charges.
There is one caution though, you have to make at least 10 chargeable calls a month or you will be charged £6.80 for the month in which you havent made a call.
Beeville, I have pmed you my email address for BE promo. Waiting for your reply.