Grill won't stay lit

Hi, We have a 2010 Sprite with a similar cooker. (3 burner Caprice) We have had it for 3 years now and the grill was never great. The grill would just about light with a clean blue flame right at the back then eventually the thermocouple would keep it alight, but with very poor heat near the front. One side went out regularly. We use propane so I wondered if it was related to gas pressure.However:

As I had some time to spare (furloughed), I took the oven out and worked out how to get the injector out. The feed pipe is held in with a glorified C clip which is just levered out. The pipe and jet can then be moved enough to get the injector out.The injector itself needs a 7mm spanner (I used a combination type as the ring is then able to get a good grip) and held the pipe body in a spanner on its flatted sides.

The jet is threadlocked in place and needs some effort to release it. Once removed, the jet orifice face was found to covered in a kind of greasey gunge. Cleaning in paraffin and blowing the jet clear looked like an improvement. DO NOT probe the jet with wire etc. This could enlarge it and  cause poor combustion (yellow flames etc.)

I then turned the cooker on its back and tapped the burner with a screwdriver which disloged some (but not much) fine rust.

Re-assembly was simply a reverse of disassembly. I used a toothpick to smear a little threadlock on the injector - we are trying not to block it up again!  The C clip will only fit one way with the tag accessible for removal. It needs a wide jawed plier to finally clip it in once placed by hand.

I re-fitted the cooker and checked the connection for leaks using a foam test liquid and all was fine.

Fingers crossed, and fired up the hobs - no problem. Turned on the grill and it lit instantly, with the button only needing to be held for two or three seconds. The grill was a nice cherry red in about 30 seconds and I suspect we will now be able to burn toast like never before.

On another tack, the fridge would not fire up on gas just after a service. It seems that some rust or soot or dust or dead insect had dropped on to the burner, but whilst checking around the burner, I noticed that  the grommet for the thermocouple had not been refitted correctly when the thermocouple was replaced by the dealer. I pushed it back in as it protects the tube wher it come through the burner support. A quick go with the hoover soon cleared the burner and it has been fine since. 

I must be getting cynnical in my old age but I would suggest that whenever anything like that is done by a dealer it is worth just checking to make sure everything is back in situ.

Thetford oven/grill in a Basecamp 2: Same problem, exactly as described.

Two minutes to mend with a small ball of aluminium foil in the hole on the back of the knob. Would only have been one minute if I could've found the aluminium foil without turning out three cupboards.