They are anywhere from £100 to £300 last time i looked. But you NEED picture of the heads. This is the part that is most likely to be in need of attention. They MAY be able to be fixed, which will cost you a matter of £100 per head. or they replaced, which... well u cant really buy mint condition heads like that.
It is a minefield and one that I toyed with for a long time. I now use a combination of software; delays, distortion and reverb. Then if i really want to i record that to an old NAD tape deck i have.
It sounds pretty close. The only thing lacking is wow and flutter, although this wasnt that noticeable on the copicat i spent time with.
Reel to reels and various tape decks this long in their life are a real comitment to maintain.
I would hate to put you off, but i learnt the hard way.