Hi Dougal - would you mind posting some pictures please? From my perspective I don't think 200e is unreasonable and I also don't like to see folk trying to belittle what you are asking as it's really not all about what the technology is in comparison to todays technology or what it can or can't do because if it were your setup would be almost worthless but as it is I think your setup - as long as it's in as nice condition as you say it is (and I'm sure it is) - it's all about desirablility and therefore THAT is what should drive the price. After all - that's what drives the traditional antique market.
Personally - I like buying the stuff I could never have afforded when the kit came out and from there Ive gone on to collect more obscure stuff - just to have it.
Even if I don't end up buying your kit I still think 200e is a pretty decent deal
John