F1 in stereo

Sir,

I see from your advertising pages that an ex-Surtees 1962 F1 Lola is described as a Grand Prix winner, but this is incorrect as the F1 race it won was a non-championship event at Mallory Park on Whit Monday, 1962.

On the same day Innes Ireland won an F1 race at Crystal Palace in a Lotus 24, also recently advertised for sale in your pages. Am I right in thinking this was the only occasion on which two F1 races have been held in the same country on the same day but at different circuits?

Bill Watt, Minehead, Somerset