I went to the RM auction at Battersea Park on 28 October. Hammer prices were:
1956 Aceca Bristol Chassis BE571. Tidy but not outstanding £65,000
1973 428 Chassis CF66 Fastback, auto. Reasonable white paint with some blemishes. The dreaded black underseal over all the lower parts of the body. Interior and under bonnet looked very tired. £100,000 (not a typo!)
1966 Invalid car. £1,400
1912 Delivery box van Chassis 1673. Immaculate £20,000
1913 Sociable Chassis 1750. Immaculate £36,000
1965 427 Competition Cobra. Chassis CSX 3006. Immaculate but not sold at £525,000.
All except the Cobra were ex-John Moir in New Hampshire. According to the catalogue, they are were registered in USA and in London on temporary import bonds which must be cancelled either by exporting from UK or by paying import duty and applicable VAT. Plus of course buyer's premium of 10% + VAT thereon. That lot in total is + 38% on hammer price but I guess that a car such as the 428 on which UK purchase tax was originally paid would not be subject to VAT if kept in the UK. The total would then be +21.5% on hammer price.
All of which introduces an unknown factor into interpreting auction prices but 100k for this 428 suggests they may be moving into new price territory.
Michael