I think so - should run for 10-15 seconds and then stop once all pressured up (based in my TD5). If you have run out of fuel or changed the filter etc. it can run for a good long time repeatedly to prime. If it runs endlessly - start looking for where the fuel might be going.
Thanks for the pictures. You live and learn! Just removed fuses for fbh so isolated that part. Pump still running.
Got to stop now my better half has pulled the garage fuse. She's so subtle!
Found the relay, swapped with a proven new one. EUREKA!!!!!! Pump runs for 15 seconds then stops. Many thanks Jimsky Korsokov, Arctic2 & guineafowl21for all your help. If ever we meet I owe you one.