Double-barrelling

You sign the register in your original name. The name change is done afterwards using the marriage certificate

I did exactly this.

Sign the register in your old name.

Then get a deed poll - this is the bit that's different to just taking your husband's name without double-barrelling. You can do it yourself, but I paid a tenner or something for some official looking ones.

Then change everything you need to - passport, banks ect.

Pixie you sang just do it with your marriage cert if you're double-barrelling. It's counted as a whole new name, so you need a deep poll.

This suggests otherwise:

A double-barrelled surname

If​‌‌‌​‌‌ ​‌‌‌​‌​you​‌‌‌​‌​ ​‌‌‌​‌‌and​‌​‌‌‌‌ ​‌‌​​​​your​‌‌​​‌‌ ​‌‌​​‌‌partner​‌‌​​​​ ​‌‌‌​​‌want​‌‌‌​​‌ ​‌‌​‌‌​to​‌‌‌‌​​ ​‌‌‌​‌​take​‌‌​​‌‌ ​‌​‌​‌‌each​‌‌‌​‌‌ ​‌​‌​‌​other’s​‌‌​‌​​ ​​​‌‌‌name​​‌‌‌​ ​​‌‌​‌as​​‌​​‌ ​​​‌‌​a​​‌​​‌ ​​‌​​​double-barrelled surnameand it’s clear how the name is derived,then your marriage certificate is sufficient evidence of your name change— you don’t need a deed poll.

Note that if itisn’tclear how the double-barrelled surname is derived, then the name will be considered a new surname, and you’ll need a deed poll as evidence of your name change. So for example, if your surname isJones and your partner’s name isSmith, thenJones-SmithandSmith Joneswould both be clearly derived from your respective surnames, and a deed poll isn’t necessary to change your name. (It doesn’t matter what order you put the surnames or whether or not you use a hyphen.) However the surnameCox-Jones-Smithisn’t clearly derived because it introduces an extra element.

Although double-barrelled surnames are becoming more popular, you may still have difficulties having your marriage certificate accepted by some independent organisations, such as banks, so it’s a good idea to renew your passportfirst. An updated passport is strong proof of your new name, and organisations are legally required to recognise your change of details under theGDPR.

If, on the other hand, you aren’t planning on updating your passport in the near future (it’s an extra cost of £75.50, and it’s not a legal requirement to have it updated), then you might consider changing your name by deed poll, to save yourself any possible hassle.

deedpolloffice.com/advice/woman-getting-married