White goods

Spain  uses 220-230v at 50Hz, fairly similar to the UK, where 230-240v at 50Hz is used. Most appliances you buy in the UK or in Spain are rated between 220-240v so should work equally well in either country.

however, buying most things in Spain proved to be the best for us. It’s quite normal here for the shop to deliver, and install even plumbing where required in the purchase price. They also take away your old machine if that applies. 

buy new here and save the removal costs and customs problems lots of different options to buy and as Lmj18 said they will install for you.

There is no difference in voltage UK 230v  50hz and Spain 230v 50hz all you need to do is cut the UK plug off and fit a Spanish one if you bring your appliances with you 

no need to cut the plug off just use an adapter

Your UK appliances will work here, but unless you are emotionally attached to them you will find it a great deal less hassle (and probably cheaper) to buy new ones here.  Especially with things like fridges which unless they are boxed and crated up properly (as in the way they came from shop) may suffer damage to compressor or other components in a lengthy move, necesitating repair or renewal anyway.

I know fridges in particular don’t like to be moved once in situ

Yep, use an adaptor just like a holiday maker. Er no holiday adaptors are designed just for that, a holiday.

As an electrician I cant remember how many times I have had to replace sockets and wiring that have overheated due to long term use. So cut the uk plug off throw it in the nearest bin and fit a spanish one. Better still get a qualified electrician to do it for you.

My dad was an electrician - he taught me well the dangers of terminals not tightly fastened, allowing the neutral or live to burn up.  Introducing an adaptor, no matter how snug fitting, introduces that element of movement and yes, extended use will eventually see either the socket, the plug or the adapter - or all three - char and then burn up.  If you’re lucky it just means a replacement socket and plug, maybe some new wiring pulled through.

If you’re unlucky … a new house.

I rest my case 

Thank you everyone. I think we will save ourselves the trouble and either rent part furnished or buy new.