Fused spur and sinks

[Harnser]

I have a small unheated downstairs toilet and want to add an electric heated towel rail to take the edge off the cold.

Because it's small I'm looking to see if there's space before I go any further. I understand the towel rail will need a fused spur and there might be problems putting this near a sink.

I Googled and saw no consensus whether a sink is outside zone 2; has zone 2 above it for 0.6m around the taps, or it descends to floor level. So... how far from a sink does the fused spur need to be?

 

[Harnser]

There is no zone around a sink.

https://electrical.theiet.org/media/1450/section-701.pdf

Whilst there is no zone around a sink you want to generally keep them 300mm away from the bowl.

Thanks. So the fused spur could be anywhere in the highlighted area? It's a stud wall and right under the sink matches with where the power is in the next room, so that would be ideal if allowed.

 

[Harnser]

If it were me, I would have the spur under the sink trap, cut out a fast fix box and feed the cable from the towel rail in the void of the wall and in to the back of the spur. I'd then box in the trap leaving a nice neat finish.

I like that idea as it would look tidy, but how would you get the cable past the stud(s) in the wall without removing plasterboard at each to drill a hole in the stud? I'm assuming each stud was a solid bit of 4x2.