Hi - we moved to Spain a few years ago, bought a house and my wife set up a business as self-employed and pays Spanish national insurance and taxes. She is completely above board and has as an accountant who submits her paperwork in the normal Spanish fashion.
When we left he UK we had an overdraft of around 8000 pounds which we slowly paid off in its entirety.

Now, because of financial hardship, we are looking at ad-hoc ways to supplement our income and I need some advice on the following:
- If I was to begin working in the “black” and people pay for my services as a guide (walking, cycling etc.) and pay an agreed fee into my UK bank account how will the bank treat these inward payments? Is there a trigger point where they are obliged to ask questions about where the money is coming from or what it is for?

- The same type of question again different scenario.  I would be receiving payments in the UK account for organizing golf trips and charging the guests a fee for airport transfers, hotel accommodation etc.

The money that is paid into the UK account would be used to pay for the Spanish accommodation for the guests, the Spanish taxis/coaches to pick them up etc. via a a UK credit card.

Would these payments into my UK account remain invisible to the Spanish Tax authorites?

Any thoughts?