Hi, not to sure what it's worth. You can pick them up off eBay for a couple of hundred quid. It's running the old K series mill which does put alot of people off as you can't get parts for these mills any longer and piston/sleeves, starter shafts, pull starts/roto starts cannot be found for love nor money. I have 4 of these mills myself and love them to bits but I know the problem with getting parts aswell.
Would be worth alot more money if you broke it and sold the parts off on eBay. May take a while to off load all the parts but would probably fetch a good 500 quid that way. The spare parts you have there will probably fetch 100 quid on there own.
The 25 depending on condition and looks, These will go on ebay anywhere from £100 up to £190 if its a runner. Seen doggie ones go for as little as £85+postage, blinged up ones fetching £250+.