Injector Bolts

Good afternoon all.

After getting the smoke issue sorted, the car passed its MoT test and was fine...for a month. The garage that did the work cleaned the injectors and all was good until earlier this week and the smoke has returned. However, I was told the problem will be with the injector tips/nozzles and they will need replacing. The garage that dealt with it has recently closed, so I can't go back there but I am capable to do this part myself.

What I'd like to know is :- 

Are the injector clamp bolts the same size for the CAYC and CXXB engines?

Are the injector tips/nozzles the same for the CAYC and CXXB engines.

I rang the 'local' Skoda dealer and they weren't sure if there was a difference (the last bolts bought from there were 10mm too short and they were ordered by chassis number). They said there is no difference in the injector tips but from previous things, I don't trust them.

Thanks in advance.