I got £420 on ebay for my rubbish condition, high mileage ’99 406 (that also had knackered power steering at the previous MOT which got bodged for ~£50). I’d be amazed if you couldn’t get £400+ on ebay for a diesel Golf – also no hassle, as you just ignore any messages from people wanting to end early, and just have to be in the once for the winning bidder to collect. As others have said, if things are tight enough that you’re bothered about £60 of diesel, then I’m amazed that you’re not interested in another couple of hundred pounds.
Not that I can work out why you tanked it when you knew you were getting rid – I only put £10 or £20 in the last few times I filled mine as I wasn’t quite sure when it was going and didn’t want to give away fuel (the warning light was on by the time I did sell!)
Just another quick one – does it have VED left, and if so do make sure you get that to chop in not the dealer (and if the dealer’s £200 includes having that then it’s an even worse deal – my £420 was without any VED).