Write to their press officer - most large companies usually have a person who deals with publicity etc. Give a brief but detailed explanation of your cause, and why you (politely) think the company should give you a donation.

In order to get a charity car donation it will require the help of large businesses and manufacturers. Possible UK manufacturers may be companies such as Ford and Vauxhall as they are car dealerships and may be able to do a good price for the charities.

Donation is the correct spelling.

Organ donation involves the donation of the heart, liver, kidneys, etc. Tissue donation involves the donation of "non-organs," such as corneas, skin, bones, connective tissue, etc.

[Debit] Cash

[Credit] Donation