I’d say at $15k that car is fairly priced at the upped end of the market. With less than 2500 (about 200 of those being LHD) Mk1 Lotus Cortina’s built back in the day genuine cars are becoming very hard to find. In today’s market a solid street car will easily bring US$30k-$40k here in the states.
In fact with core engines valued at $3k-$4k, steering wheels going for $1.5k, dash binnacles with gauges commanding $1k, rolling shells $3k-$4k and all of the other unique parts combined it could probably be parted out for a profit.
Btw: the car listed is actually a 1966.
For more information check out:
http://www.lotuscortina.net/Homex.html
http://lotus-cortina.com/