Ashgood usually offer a 3 month warranty as standard, granted not as good as the Porsche one though.
Good news on potentially finding one though!
To be honest, it is Porsche warranty or nothing for me and a car with no warranty would have to go through a 111 and pass that, we all know that even if it passes Porsche could still refuse warranty unless you were to fit say latest N2 cup tyres all round, a friend with an RS who is selling his literally did this for next customer and got hit with a 5k bill as to put warranty on the car OPC insisted it had new N2 cups all round, couple of other minor items, then cost of warranty and service it cost him 5k, he did offer me his RS but its white and for me I wanted UV, Guards or Lava or a PTS really.