Heater Control Panel removal & replacing


I have a Non Air Con Heater control panel and the heating is not working on any of the settings.

I know it is not the resister as I had this into the garage about 8 months ago and it was a fuse that had blown but the heating was also erratic when on (it was like a loose connection and the heating would sometimes go off when I went over a bump).

Due to the dash having to come out, it turned out very expensive therefore I am thinking of putting in a 2nd hand control panel myself.

I have a Haynes manual and had the dash out numerous times but I was wondering if anybody advise if it is easy to put in a replacement heating panel? The cable connectors are making me think this a difficult task?

Any help would be appreciated.