Interesting one this. Party political donations are very rare by UK PLCs these days (except Caledonia...) and are usually opposed by institutions (unless they donate too....). As a result most of the time when companies seek authorities wit a political donations resolution a) they are seeking authority to incur expenditure rather than make donations and b) the resolutions pass very, very easily.
Betfair just got a 29.5% vote against its resolution seeking authority to make political donations. This is almost certainly because it did make party political donations. Actually these were in Germany - to the CDU and FDP. Considering that a fair chunk of Betfair's shares are held by directors this looks to have been a very large revolt by independent shareholders.