I’ve got a 1993 V6 TR Magna and I suspect that I have some blocked injectors (due to me running too much on LPG and not enough on petrol). If I want to take the injectors out and get them cleaned, what else has to be removed in the process and what parts am I likely to need when putting them back in?..gaskets?..O-rings? etc? and good place to get them in north eastern suburbs of Melbourne?

and what is the torque requirement on the injectors? (and any other bits that have to be replaced)

Injectors just slide into the inlet manifold holes and they will get new "O" rings top and bottom by the place that services them for you.
Fuel rail bolts 10-13nm. Change your main fuel filter at the same time as well. Vee