Hello - I have purchased and was fitting a new PCB for the Baxi Solo 3PF when I came to fit the mains leads to the board they seem to need a push fit attachment that was NOT on the one I took off - all the rest of the wires are there but some jackass decided to change the fitting so they cant be tightened from the top ... what is this fitting called and where can I get a push fitting for the wires from the mains to the PCB ... one is a three pin the other is a completely different four pin with a guiding slot!! ... Help! Steve 9.11.12