How to find NIE number and bank details

Hi about 10 years ago I was buying a new build apartment in Tenerife
When I went to pay deposit I was taken to get NIE number and also opened a bank account with Santander.
The builder went bust so I never got the apartment
I lost every bit of paperwork regarding NIE number and bank details
Is there any way I can find these out. I’m living in UK at the moment

My Daughter & Husband put a Deposit on a new property in Tenerife but didn't follow it up. The Bank wrote to her after a few years asking them to get in touch. It came from a Bank in London. Try getting in touch with the Bank They only paid £1000 so didn't bother.

I’ve moved house twice since then so they wouldn’t know where to find me

Try getting in touch with the Head Office which could be in London and ask their advice.

The NIE number is loosely similar to a UK NI number, letters and numbers, but Banks also use a NIF number which is all numerical. It turns out my Bank, Sabadell, use my Passport number as my NIF number so if you know your passport number when you 1st applied (probably changed now after 10 years) it would be a good place to start when you contact Santander? . . . .