He's right you know.
Sealey draper 2-12Nm about £25 in the deals: bombproof, really easy to use, lifetime warranty. I have 3 Sealey t/wrenches (2 - 12, 12 - 60 & mahooosif for m/bike swing arms, wheel nuts, etc and have used them for years with no problems atall). The 2 - 12 is bicycle use only and really nice to use.
Snap On - about a million quid nut probably one of the best you can buy but so lovely you don't mind paying for it.
B&Q do one 2 - 12Nm for about £20.
Alternatively I think Ritchey (amongst others) do torque keys - pre set tourque settings, generally come with in built 5mm bit but you can remove them and then use any size bit you want. Cheapest option for once in a year use.
I bought a separate box of multi sized Allen, torx, security and screwdriver bits from Sealey Draper - about £20 but covers every size imaginable and so useful for working on various bikes (eg Campy using their toro bits and Shimano using Allen). About the size of a small book, hard plastic case so very portable and will last a lifetime.