Can you help identify this vintage car?

I recently found this pic on the net. It shows my great grandad at home with his car. This car was probably not too many years old at the time the photo was taken, which was in 1929 . The radiator insignia seems to resemble a Maltese Cross I'd appreciate any contributions from the UCP experts as to identifying what make/model it was?

• Ghia 1500 GT
• Ford Gran Torino Sport 1973
• Reeves Sextoauto
• Wartburg Melkus RS 1000
• Rinspeed Porsches
• 1919 Rolls-Royce 1EX