My guess is that £1200 is underpriced - a lot depends on condition of the chassis.
At this age the vehicle will likely be bought by someone KNOWING they will need to do repairs and to give TLC
When I sold my VW (30 year old and 250,000 miles on the clock albeit on the third engine) I sold it for what I had paid for it in 1972. The buyers ran it for some 6 more years but did not administer enough TLC and the rust worm eventually caught up with it
My advice would be to book a sales pitch at a VW rally eg there will be one at Tatton Park in August (http://www.volkswest.co.uk/shows.html
). It costs £10 for a space in the sales field and you will get lots of VW oriented folk coming to look. That was how I sold mine.