Well, i attempted to fix the broken rear wiper/ mash of cables yesterday and am fairly happy with the result.
The rear wiper is now working again but only when you spray the front windscreen first. Some swapping of wires didn't help the problem and after a couple of hours on this yesterday I gave up trying but i will have another go at the weekend.
Connections wise i'm happy though as they are all now neat and tidy. Taped it up until i can order a new grommet but because i've used bullet connectors on all the wires i'll be able to just pull them apart, slide them through the new grommet and connect them all back together!!
Will be interesting to see how the connections hold up under the stress of the boot opening and closing, i used bullet connectors as they should have a bit of play in them and if they do stretch, it should just be a case of pushing the connectors back together again!