Hi Rob,
I agree with Kenbo, the banks have to provide non-resident tax certificates to the Spanish authorities every 2 years, so I don't think it's a coincidence that you've owned your property for 2 years and this is your first charge. The amount sounds about right too - although more than half of it will be the bank's "admin fee"!
If you're not planning to become resident in Spain, I would also recommend switching to an online bank with an EU IBAN, such as Wise, so that you can also pay your direct debits from it and ditch your expensive Spanish bank.
Kind regards,
Kim