First of all you have some buy to let property.
Can you save money on your current borrowing? Click on http://www.portfolioreview.co.uk/can_you_save_money.html
Or how about use your property to buy some more? Click on http://www.portuguese-villas.co.uk.
This site suggests some great investment opportunities in Portugal. Take a look at http://www.portuguese-villas.co.uk/opportunities.htm
This has some other ideas ,such as other countries and other investment opportunities.