wrote
| Whilst we are on the subject, historically why do the
| majority of shavers come with a two pin plug that needs
| an adaptor?

Because they're intended for shaver sockets, which are
(a) two-pin
(b) the only type of socket that may be installed in a bathroom
(c) unearthed because shavers are double insulated
(d) shaped that way so that you can't plug anything other than a shaver (or
toothbrush etc) into them.

| We use a 3 pin to 2 pin adaptor for UK electrical items
| when we travel to mainland Europe.

Which is fine *provided* your equipment is double insulated. Even the French
are installing earthed sockets these days.

Owain