Andy
Welcome to Beoworld. I am sorry to hear about your father, it sounds like he would have liked it here!
Ebay can be a good place to find buyers. Some of this kit is harder to sell than others and nearly all of it will be quite hard to post so it would be useful if you could tell us where to live.
Condition is really important with second-hand B&O as older items in poor condition can be worth very little. Working cartridges on the turntables would be a big plus, a working cartridge auctioned on it's own can fetch more than a cartridge an turntable together.
Assuming everything is in good working order approximate prices you might expect are
Beosystem 4500 comprising: Beomaster 4500, Beocord 4500, Beogram CD 4500 - £200 - £400 A great system and I would strongly urge you to keep it and use it! It really is much to good to sell for the money it will fetch.
Beogram 3000 - There were two turntables with this model number, you would need to look at the products section on this site or post a picture to determin which one!
Beogram 1200 £20.(without cartridge)
Beogram 1500 £20.(without cartridge)
Beomaster 1600 (£20-40)
Beocenter 7002 (£50 -100)
Beocenter 2200 (£20-£40 without cartridge)
Beovox RL60 (pair) (£50-100)
Beovox X25 (pair) (£10)
Beovox 3702 (pair) (£20-50)
Beovox 2700 (pair) (£20-50)
A fully-tested working cartrigdge will fetch £30-£70 on eBay. The stylus cannot be replaced so a non-working cartridge is worth nothing.
Good luck with the sales!
Simon