Transit engine swap problems

[Gazdon]

Morning people I'm new to the forum and In need of some help I have a 56 mk7 ford transit that I love and plan of keeping her the problem is one of the previous owners has done a engine swap and have replaced the loom from what I can see from a older transit because it has the older clocks and hazard warning switch and stereo fitted that doesn't look good but I can live with that the main problem is the abs light is on and after close inspection I found the main plug that fits onto the abs pump doesn't fit because the older loom was fitted so doesn't fit what can I do because when it comes to mot time I will be in trouble why the previous owners just didn't fit the same engine is beyond me any help will be appreciated