Update

I have decided I need to lose 2/3 of the crap that's in my flat.

To this end, I have booked my cleaner to come and help me next Saturday (not this Saturday coming, the next one) and we'll go through some of my stuff, books and clothes for a start, and get it put into boxes and bags, and I'll book Any Junk to come and take it all away. They're a little more expensive than some of the options, but they reckon to divert 96% from landfill.