Well, looks like the car is off to the garage.
Injectors 2 and 4 were ultrasonically cleaned this afternoon. Put it all back together with 2 and 4 swapped over and just started her up. Misfire still present and no improvement.
I dare say next step for them will be a compression test. I'm not 100% but I'd say it's likely they will want to remove and break down the engine depending on the compression test results.
Id like to think I'd get a phone call and be told 'ah, it's skipped a tooth Mr W but don't worry there was no damage done and we and re-timed it and all is well'... but I don't think my luck is all that
Bad times