Have you tried MyDonate from BT?

MyDonate is a not-for-profit, online fundraising service for UK charities.  This service provides a secure, easy-to-use way for people to donate money to the charity of their choice.

BT does not charge you or us for making the donation. The only charge made against your donation is a credit/debit card charge (1.3% of donation on credit cards and 15p for each debit card transaction) to cover bank charges.

If you are a Uk Tax payer and tick the Gift Aid box BT will also collect the gift aid for us from HMRC. This adds to your donation at no cost to you.

A £10 donation with gift aid will cost you £10 and we recieve £12.35 (£10 plus £2.50 gift aid less 15p bank cost)

Do you know about Amazon Smile?

 You shop. Amazon gives.
Amazon donates 0.5% of the net purchase price (excluding VAT, returns and shipping fees) of eligible purchases to the charitable organisation of your choice.

AmazonSmile is the same Amazon you know. Same products, same prices, same service.

If you already have an account with Amazon a switch to buying via the smile.amazon.co.uk link will use your existing account.

To select our charity, type 'grandad' in the charity search field on the smile.amazon.co.uk site.