Og readings
 

Silly question
Should it be taken when the wort is ready to take yeast eg at 22c ish or is it ok to take before its get down to temp?

22C is on the warm side, but that would be ok. Most hydrometers are calibrated for 15.6C. I normally add the yeast at about 18C, which is a much better fermentation temperature and gives the best tasting beer.

Cheers I'm just splitting my wort into 2 demijohns so wanted to make sure first

So I will take 2 ogs just in case