I work for an agency at just one firm hauling firms own goods,when i started i had to have full days training on how to do it,the company have now started do do back loads for someone else and all there own drivers have had to be trained because of what they carry but not agency drivers.
What i want to no is would you do the job or be like me and say no until trained.
Depends what your carrying, If they are just backloading say 24 pallets of toilet roll, I reckon I wouldn’t need training 
If however it was something highly specialised, then you are probably within your rights to ask for some.
it’s odd shaped steel and metalwork
It wouldn’t bother me personally, but if your not confident and think you need some training ask them, they must be training thier own drivers for a reason 
mac12:
What i want to no is would you do the job or be like me and say no until trained.
mac12:
it’s odd shaped steel and metalwork
Personally I’d be happy to do it, I’ve carried some varied loads in the past and never thought of asking for special training to do it 
I’m probably going to get slain by the H&S extremists for saying this but it is after-all what driving large goods vehicles is all about