Baxi 105e Flue problem

My daughter had a problem with her Baxi combi boiler which seemed to be connected with the flue. Originally it seemed to be linked with a broken clamp around the flue and as a result the pressure differential switch was not activating. Repairing this helped but then it went off again at this point we found some insulation had dislodged and fell on the burners but not until we had tried to adjust the switch. I noted before we adjusted switch it seemed to have a centre position where a small pressure differential caused it to change but larger one caused it to return and after fiddling this no longer seems to be the case. So was the switch faulty to start with or faulty after we tried to adjust. Also three cables on the switch blue N/C then brown and black when my son-in-law removed and replaced the brown was on common and black on N/O but the instructions on lid say brown on N/O and black or common tried both no luck. The Brown is live and unless connected to black on start the fan does not run. Boiler type 105e I think we will need to get a baxi engineer to replace the boiler lining but if I could get it to run to give hot water while waiting it would be bonus can anyone help?
Eric

If you leave it alone, and turned off till the baxi engineer sorts it out, you could consider the fact that your daughter is not in danger of being killed by your stupidity a bonus.

as above.

Well fixed today we had daughter living with us while it was fixed there was as it turned out no way we could have fixed it as main board had failed took 4 days to get fixed by British Gas but that did include weekend.
That has made my mind up anyway I was considering renewing my boiler for a more modern one but now I'll stick with old one until it dies prefer to pay a little more for gas and have reliable boiler than save on gas and it break down.
Thanks Eric