Thanks Ed. I know I don't 'need' one but it's handy to have so I can just give it a quick tighten if I notice it's too slack on the way to work or whatever. Do they all fit the Steamroller dropouts do you know?
If it gotten slack, it simply wasn't tight enough to begin with, ramming a folded tea towel between the tyres and seat tube, aligned the wheel and tighten the nuts as much as you can will sufficient.
You don't need a chain tug (a tea towel or tennis ball is apt) but any cheap chain tug will do such as the DMR one.