So after Marcela had left for work, I removed the bathroom sink, before I damaged it, and then cleaned off all the epoxy and other mixtures I had tried, in my attempts to seal the leak, the fact that it was easy
Fortunately, all went well, so I sanded the cut, and then applied special PVC glue Diego had left me, which will set even if wet, and attached a new fitting, this would give me more space, as previously there were two fittings. I then left it to set for half an hour.
Before assembling the tap fitting, so as not to disturb the joint.
Then it was time to replace the sink and waste
That done I went back out into the road, and turned the water back on, but at low pressure, and ran back to the house, in case there was a flood, I needn't have worried, it was totally dry, and has remained so ever since...job done!