Napier Railton Special. John Cobb leads F W Dixon's Riley. BRDC 500 miles race Brooklands 1934

This one baffles me as I thought Kay Petre retired after her 1937 accident and did not race at Brooklandsa again but the date on her driver's armband appears to be 1938... can anyone confirm?
Photo available 7x5 or 10x7 inches ( 175x125mm or 250x175mm)
 

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