[LargeFormat] Rodenstock Sironar-N (240mm f5.6) question

[Gavin Hubbard]

Hello list

I'm looking at buying some equipment from a retiring local pro 
photographer.

The item I'm most interested in is a nice Rodenstock Sironar-N 240mm 
MC f5.6 lens. It is mounted on a Copal 3 shutter with a Toyo lens board. 
The original lens caps are included. The serial number indicates a 
manufacturing date of ~1987 and the lens has had one owner since new. 
The condition is very good and the glass is flawless.

I've been asked to 'make a fair offer' for the lens. Unfortunately the 
market in NZ is too small here to get any meaningful info from local 
dealers.

So in a nutshell, what would be a fair price to offer for this lens? I've had 
a look on EBay but there aren't enough data points there.

Thanks in advance for your help.

Best regards,

Gavin Hubbard