Lem wrote:

Are surge protectors on the main power supply actually needed in
the UK?

here in the UK we have few overhead mains power lines and have a
relatively steady mains power supply when compared to many other
countries (including the US).

Wasn't there a big black out around London last year just after the
North American black out?

However there seem to be very many surge protector products
advertised for sale in the UK (Argos, Maplins, etc).

A surge protector can be very simple, doesn't need to cost a lot.

I am quite sure it is not bad practice to use a surge protector but
in fact I have never known anyone who has has a problem from a
surge coming in through the power supply.

My first PSU was killed by a spike, but then you don't know me. At a
place where I once worked, they had problems with fuse timings on the
entire building, the engineers would sometimes test which fuses went
first, thereby inducing enormous currents in the power network.

So personally I don't bother using a surge protector on my PC.

Am I being too complacent?

Entirely up to you.