UPDATE!!

It rained heavily until lunch time and we got quite wet on the dog walk. We had lunch in a local Italian restaurant which was lovely. We stopped off at my sister's house to feed the cat and discovered water dripping out of the boiler. We rang the gas engineer, four hours later the heating system was drained ready for a new heat exchanger to be fitted on Thursday.
So ...... no blips today.  Emergency -  Easter bunny update!!