Have you tried login onto to 'What Car' and see what their valuation comes in at. Don't know how 'What Car' compares to 'Glasses' guide but it might give you an outline guide. Of course, at the end of the day, it's the £ notes you get that is the real valuation.
ive seen the vm engine going for £400 and fuel pump for £200 also no1 injector for £129 and other dumb prices for rad and fan so i would break it and make alot more than that ps if you do can have your viscous fan