a solicitor is too expensise
Considering your have already shelled out £20k, and potentially may have to shell out "a lot more" to get the job finished, in initial consultation with a solicitor wouldn't cost a lot at all. It;s really a myth that they are expensive, OK so they are, but if you are canny then you can at least get some initial advice without spending a lot.
also we wre told that we would probably not have any money back
One thing I can guarantee is that if you don't get an expert in to survey what you have, then you won't get anything back. If, and this is only an
IF the work is really bad and the surveyor backs that up - you stand a chance of getting up to £5k back quite cheaply (see what I;ve written earlier about the small claims court). My guess based on what I've seen so far is that you could take the builder to court and get a judgement against him.
Getting a judgement isn't the same as getting your money, but it's a start as he then has a judgement against his name (I'd guess possibly to add to the others he might already have). If he can't, or won't, pay up - then you'd have the option of having him declared bankrupt. It costs to do that, but you'd have the satisfaction of making his life miserable in return for doing that to you.
and the lawyer wouuld get his money back either
You'd be paying him, he'd get his money from you.
I think you've been taking advice from the wrong people - and you seem intent ion ignoring what people here have told you.
Don't delay any more - get an expert in. If he says you've had £20k worth of work then at least you'll know that. If you haven't then you can discuss how to move forward. If there's work which is so substandard that it's a hazard - then you'll also know that before it gets even more costly to put it right.
But
WE (or at least the experts here)
DON'T KNOW from a few photos.