I would guess its current value is around £28.99.
Collectables don't have a fixed value, prices fluctuate wildly and the only reliable source of prices is ebay completed items. I recently sold my
rarer and more sought after Martini Renault for £70, but that was made from almost all brand new parts with an undamaged and correctly stickered body. I also bought a March BMW in similar condition to the one you've bought a few months ago with plenty of spares and extra F1 bodies for £34.
You could try taking the radio gear out, but there are very few collectors interested in hunting down period correct radio gear and no one is going to try and run that radio so it's not worth anything out of the car. Splitting the car for parts would leave you with an awful lot of leftover bits and not much sold as the rarity of the cars means anyone looking for spares will be looking for new or perfect condition ones.
Best way of selling it on is to clean it up, maybe strip the body as well, and if it's in good condition make sure you use plenty of decent pictures to show it's good points.