There is nothing wrong with the halford stuff, I have two of them that cover everything:
This one does nearly every job you need it for ->
http://www.halfords.com/webapp/wcs/s...egoryId_165469
There are only a few fasteners that require more than 60Nm, mostly structural stuff, wheels nuts etc. Everything else is mostly 10-30Nm, although there are some that are 5Nm.
For a second wrench to cover the stuff over 60Nm then here ->
http://www.halfords.com/webapp/wcs/s...egoryId_165469
Machine Mart is always a good place to look for tools, and there is usually a shop within riding distance.
Many to choose from ->
http://www.machinemart.co.uk/shop/se...ype/any/page/1
Ideally. something that ranges from 5 - 60Nm will be good for most stuff on the bike. You may need to consider a 3/8 to 1/2 adapter too depending on what you purchase, sometimes it can be difficult to get the 1/2 sockets into places. You'll need one going the other way too, in case your 3/8 drive wants to use a 1/2 socket - depends on your wrench and your socket set to get the right match.