Just wondering if you have mis-remembered the circumstances in some way, something I find I do with increasing ease...
eg: Around 1980 a PA-31 owned by Lotus crashed after a loss of control while apparently doing aerobatics - it was being ferried back to Hethel after maintenance at Stapleford Tawney. It broke up. Right sort of timeframe, exec aircraft...
I did go through an HS-125 production list and didn't spot anything relevant - though there do appear to be an astonishing number of 40+ year old 125s still current in the US.... Or more likely the list I looked at is somewhat out of date!
Last edited by treadigraph; 1st Oct 2020 at 18:02.