Check out the Brewers Association Draught Quality Manual to help you balance your system and get the right pour. You can download the manual for free. It's pretty comprehensive.
Ya I've got a copy, it's been really handy so far, but the thing I don't get is this: I've got a Y-splitter on my co2 tank and both lines are the same length, and the lines out to the taps are the same length too, and since I know the other tap is fine I'm pretty sure it's not a balancing issue.
For the blockages, etc - should I just unscrew everything and see what I can find? I'll give it a shot tomorrow night to see what I can see - thanks for the tips all.