Popular consensus appears to be very much against BMW seal and protect, especially considering the price.
I thoroughly washed my new F10 and applied two coats of Werkstat Acrylic Jett, took the wheels off and did likewise with Poorboys sealant and the car looks great for around £25.
I see you're in Scotland; if you live anywhere near Aberdeenshire go and have a chat with these guys:
http://www.polishedbliss.co.uk/