Did a search and couldn't find a post on this topic for a couple of years so in case people still don't realise...
If you use Child safety socket covers, get rid of them! They are dangerous and they actually make sockets more dangerous not less.
Socket covers are completely unnecessary and could potentially cause a fatal accident. UK plug sockets are designed with shutters to prevent anything except a UK plug being inserted into the socket. It is extremely unlikely that a young child would be able to open these shutters, as the child would have to insert something of exactly the right size into the earth pin. This is not possible with real plugs. But socket covers hold these shutters open and introduce a range of new dangers.
Unlike real plugs, the various design faults of socket covers allow a curious child to insert them (upside down) into the earth pin only. On many sockets this opens the safety shutters and allows children access to the live contacts!
If you have these at home, please take a few minutes to read the national campaign calling for the banning of socket covers: www.fatallyflawed.org.uk