Clive Sinclair died at 81 after a long illness (probably not Covid)
'course now he is touted as being "the inventor of the pocket calculator"
(as with all "FIRST"s, it leaves out a few predecessors,such as Busicom
(1971, whose contract with Intel led to the 4004), Kilby's 1967 "Cal Tech"
at TI, etc.)
I'm not sure, but the HP35 might even have preceded the Sinclair
calculator.
As with all "FIRST"s, an entry can be saved by redefining the field.
Sinclair's was probably the first one costing 5 pounds or less.