had to replace the airlock with a blow off tube.the yeast was added to a starter made up from 120ml dry malt extract ,dissolved in 470 ml water (palmer's 1040ish mixture). The yeast is from the local microbrewery and a true top fermentor.
Any suggestions how I get the yeast out and share between 2 buckets
it's sad to see all the good yeast lying to waste in the blow off bottle. 
following daabs advice, i'll introduce cooled wort to the demijohn, giving a swill-around and then apportion amongst the two bins. 