The entry list for the British Empire Trophy race at Oulton Park in April 1958 included two Ferrari 250 Testa Rossas from the Belgian racing team Ecurie Francorchamps, to be driven by Alain de Changy and Freddy Rousselle. Here's a photograph of one of them in the paddock before the race.
It's Alain de Changy's car, serial number 0724TR - the barchetta.cc record for that car doesn't show it to have been in that race, but it's shown in the World Sports Racing Prototypes record. This car finished ninth in the race, but Freddy Rousselle didn't manage to qualify his car into the final from its heat.
NB: (20 Nov 2015) It looks as if the WSPR record is incorrect, and this is in fact 0736TR