Vodafone have a deal for fibre plus two mobile sims on a twelve month contract.
If I move house (as I hope to) within that year can I just transfer that deal to a new address?
Desperately need Spanish sims and phone numbers as would like internet for home use but torn as to what the best options are.

You should be able to, but there may be a charge to pay.

Cómo solicitar un cambio de domicilio en Vodafone

I'd check out Movistar (as well as the prices on offer under the O2 brand) as well as Digi.

Personally I don't like anything with min. contracts and only go on a non-commitment basis (sin permanencia). Never liked Vodafone much here because their prices seemed designed to be the most complicated and volatile over time.

Is it just the two mobile phones that you need in addition to home internet or will there be more numbers (kids, etc.)?

Thanks for that link.

Worth a look here

https://comparaiso.es/ofertas/internet/broadband-spain

I switched from Movistar (the package included too much I didn't need/want) to O2 and have saved 22€ a month. It has been perfect, and it is part of Movistar anyway!

If you're thinking of moving the first and most important thing has to be finding out if Vodafone actually have adequate cell coverage at the new location.

Whatever the deal no contract is worth a toss if you have no service!