I am not sure that LAC 017 sounds like an AC Bristol serial number.
1956 AC Bristol - Roadster | Classic Driver Market
This Bristol's serial number from the above link is BEX 211.
If perhaps the chassis was on the road from back in 1961 and it is some sort of AC, it would have a leaf spring chassis instead of a coil spring chassis. If that is the case, maybe it had the original body replaced with a Kirkham body? The Kirkham website says they have been around since 1994.