I'm not an expert and there are a few proper experts on this forum so you should wait to see what they say. I do have a 1926 EW (
http://www.barkshire.co.uk/bikes/DouglasEW1926.htm )and am learing about them myself and on that basis here are some comments...
It looks like you have a lot of good parts there which look like the ones on my 26.
It also looks like someone has done a lot of work on it.
The silencer shouldn't have the end piece on the 350 (not so important)
The wheel rims/tyres look 'wrong' against the mudguards. Are they too small?
From the photos, there is nothing that would worry me if I was buying.
As for price, they are not expensive bikes in restored condition and in project condition they should be quite a lot cheaper. It is very hard to get someone to give you a price over the internet as they can only ever be 'wrong'! I will stick my neck out however and duck when the rotten tomatos come flying through my monitor.
Based upon the photos if someone offered me this bike I'd probably put in a starting offer of about GBP 2000 and take it from there. Unfinished projects always cost more than you think to sort out (that is why they are unfinished). Sorting the wheels/tyres you should allow GBP 500.
If it is very nearly on the road and has spares and history and other good reasons to buy it then you might spend up to GBP 4000 if its a good one.
