using surgical spirit to clean connections before desoldeirng?

Noobian:
It turns out that the methylated spirit "aka denatured alcohol" by definition is nothing but ethanol with 10% methanol additive. So basically the Surgical spirit which you mentioned is Ethanol based, and NOT methanol based.

And that is what I said. No-one ever suggested there was a version of "Surgical spirit" based on methanol. If nothing else, it would probably be more expensive.

Noobian:
But that's B.P's version of surgical spirit, others use IsoPro with no methanol, instead of denatured alcohol.

No problem.

Noobian:
The amount of methanol in Surgical spirit is of a considerably small amount, that is after the methylated spirit has been diluted with 30% Water.

It is as stated, about 10%. Dilution with water, if performed (rather unclear from these sources), would arguably reduce this to 7%. Whether you consider this "a considerably small amount" is clearly relative.