By about Tuesday evening the beer had dropped to 1.010. I decided to leave it and see if it fermented out any more and just bottle at the weekend no matter what. It hasn't shifted any further gravity-wise, which I think really is pointing to my need to get some temperature control for fermentation sorted. That makes the ABV estimate around 3.4%.
A sneaky taste from the sample jar indicates that reducing the brew length has made the beer very bitter and unbalanced. I'm hoping if I leave it in bottles for a while it will mellow out a bit.
I've rinsed out my bottles ready to sanitise, and ready to whack the beer into the bottling bucket (of which the tap will be scrupulously checked this time). I'm off for lunch first though.