Pro is quoted as saying;
‘Mechanically it’s a blooming beautiful car, it’s [got] a 7.9- litre [engine] or something, it’s a really big motor, and I thought, “What a shame to paint on a beautiful ‘Roller’ like this.” And I thought, “But people will take more notice of this than if I painted a T-model Ford or something.” So I said, “Right, this is it.” So I painted the Rolls up. Then I had to buy another “Roller” because I couldn’t paint over it again because there was too much work in it.’
The above is from; http://education.unimelb.edu.au/__data/assets/pdf_file/0017/1105730/pro-hart.pdf