Anybody happen to know what diameter the end of a petrol pump is, the bit you stick down the filler nozzle?

From Wiki....

"Motorists occasionally pump gasoline into a diesel car by accident. The converse is almost impossible because diesel pumps have a large nozzle with a diameter of 15⁄16 inch (23.8 mm) which does not fit the 13⁄16-inch (20.6 mm) filler, and the nozzles are protected by a lock mechanism or a liftable flap......................."

cbs says

"Vehicle fitted with engines manufactured after 1993 must have a restrictor fitted............................"

I did not have one fitted at the time and it passed the IVA test last year. I guess it depends on the IVA man.

A restrictor is no longer required for IVA, but a cap lock or tether still is.