looks good, but did you try it with only one of those 10 ohm 10 watt resistors? I have a PC power supply set up almost exactly the same way, and mine worked just fine with just one...
later, you may wish to stick an lm317 in there with another binding post and a potentiometer, attached on the 12v line, which will give you one terminal adjustable between about 1.25v and 11v.
I never thought of that. Specialist lab supplies cost loads more, so to make one for £8 is good going! Looks fine, but always take care with mains electricity