You don't say what the coving is made of, you could have quite a few solutions depending upon the original preparation.
The flaking is due to moisture getting in, if it is plaster coving and was not 100% dry when painted then it will flake.
I presume it is being emulsioned, in which case you will need good quality bathroom paint and ideally let it dry throughly. There is definately moisture involved, a trip to your local builder's merchant would be helpful. I had this problem with my final coat on the bathroom ceiling, hence why I know about it. My two white coat's of paint underneith the peeling paint were fine, but not given enought time was given to the third coat to dry out, so I was reliably informed. Hope this helps
Suz, April 2010
