Hi
The £3000 figure you mention regarding gifts, relates to UK inheritance tax that may be payable on a UK tax resdent's estate upon their death.
If your mother lives overseas and has no UK assets, that figure will not be relevant in the UK. Spanish inheritance tax rules would most likely apply.
There are no income tax implications on the receipt of a cash gift unless the cash gift generates interest or dividends. These would then potentially be subject to tax.
Further guidance can be found here (
Tax on savings interest and
Tax on dividends).
Thank you