One thing remember that SD tv's wont become obsolete for maybe 30 years. There simply isnt enough bandwidth available on DTT for this to happen.
WARNING - Be very careful with Clearence Comet - I have bought a VCR and a TV off them in the past. The TV didnt work properly and they ended up having to take it back. The VCR has a bent loading mechanism, took it to the Comet in Bromborough as I was advised to do by the Clearence support telephone staff, and the store refused to refund it. They told me to take it to the service centre in B'head, who then told me take it to the nearest store and ask for a refund.
Again the store refused to issue a refund, after the Clearance support staff had contacted them to tell them to. In the end the clearance staff forced the shop to issue a refund (it wasnt like I wanted a refund, I bought the VCR again, only as brand new and for extra money in the shop there and then) and made a formal complaint with the area management about the stores refusal to issue a refund, which they should have without issue was clearly stated at the time on the website.
Im not saying the clearance staff themselves were bad, they bent over backwards to try and help me resolve the situation. But the problem was firstly that the goods were both faulty and secondly don't expect the Comet stores to offer any support or refunds (as they are supposed to, especially for smaller items), even when the clearance department tell them too!
You would be better off looking at the likes of Empire Direct/Ebuyer/Dabs/Hughes Direct for a discount price.
And HD isnt all its made out to be anyway, I have been running HD trailers and movies etc since 2005 on two different sets (expensive XD engined LG Flatron and cheaper Dual set) and to be honest they are no better then a standard transmission unless a. you are right upto the TV or b. you have a real need to see peoples hairs and wrinkles. Personally I can live without HD, I couldnt live without Sky+ on the other hand...
Just wait for UltraHD.... All these fancy HD TV's will be obsolete too in 15 years lmao!