Hi Steve , replied to your email but will post here as well :
I would be looking at two possible causes :
First check the 4 pin plug that goes to the fuel pump under the seat
Disconnect the plug from the pump and make sure there is no corrosion on either the male pins on the fuel pump itself or in the female plug on the wiring harness
Also check where the harness wiring connects to the plug for corrosion or any breaks in the wiring
I know this was a problematic area and a number of bikes had new connectors fitted under BMW warranty
If all looks OK there the next item would be either the fuel pump itself or the in line filter attached to the pump
The fact that it starts after 5-10 mins could be either the pump motor cooling down and then working OK again or the sediment settling in the filter and then allowing the fuel to pass again
Hope you can get sorted