I've ordered some Liqui Moly Diesel purge and it should arrive today. I was going to just add it to the tank but I realise that it will be more effective if run through neat. Can anyone tell me how to do this exactly. Do I need to do some sort of loop to prevent fuel being pumped from the tank or remove the fuse for the in-tank pump? 

Liqui Moly Diesel - i don't know anything about the use of this. However, do these cars have an in tank pump? I thought there was no pump other than the high pressure mechanical pump driven by the timing belt (and that is why it is so difficult to bleed the air out when changing fuel filiter etc.) I do accept that I could be wrong, I am not not claiming to be 100% certain. 

Yeah, I thought this too but the haynes manual refers to an in-tank pump (although there is every chance it is wrong). This would explain the hand priming pump as well on the early models.I'll go on the basis of it not having a pump in the tank and I'll connect the return pipe to the filter output just to make sure. In order to get the purge through the pipes I am going to have to remove the quick release connectors and use a hose union to connect an additional length of pipe to the diesel feed pipe and the return from the injectors - can someone tell me the size of the pipes? Are the 8mm or 6mm?

Here is some video someone done it in very easy way.