Crank Position Sensor... Riddle Me This?

[LPTJoe]

Right, first things first, some time back LairdScooby said I should check the wiring on my crank position sensor.

Turns out that was good advice (Thanks LS!) Today I did, look what I found....

SAM_7029 by [url=https://www.flickr.com/photos/152293344@N05/]

I traced the wires back from the sensor to the plug, shock! Whilst the internal wiring looks ok the insulation is clearly shot. Clearly I need to replace this but as usual I have a few questions

1. Could this be responsible for my odd misfire problem and lazy starts?

if the answer to question 1 is yes, then...

2. To refit does the engine need to be at TDC? Is it necessary to pull fuse 1/disconnect the battery whilst fitting? Anything special that I need to do other than simply bolting the new one on and connecting the plug?

3. Has anyone had any luck with aftermarket parts for these or is it best to stick with OEM?

As always, thanks in advance chaps. Advice/suggestions/tips/musings encouraged and appreciated