>> BT offering me another free hub phone if I renewed my contract to 18 months
Most ISPs will give you a freebie if you sign yourself up for another period.. although IMHO 18 months is rather a long time.. and not something I would personally do for the sake of a free router - particulary the HH.
>> (Only BT for my area ISP....)
Are you sure of that? Most exchanges are served by BT Wholesale - but this isnt the same as BT Broadband.
Although you may not be able to get the likes of Be.. you should still be able to choose from any of the many ISPs that use IPStream adsl.
Try putting your details in the adsl checker
http://www.kitz.co.uk/adsl/adslchecker.php if the exchange comes up as adsl enabled - then you should be able to choose any IPStream ISP.
The list on the righthand side is LLU adsl - so you can ignore that if nothing comes up.
ISPs that use IPStream are identified on this page
http://www.kitz.co.uk/adsl/isp_price_list.php as "Type 1" in the box on the column at the far right.
Also look for type 6 who will use either IPStream or LLU - depending which is available at your exchange.