No, and i think it was a bit more complicated that the way you put it.
Essentially in the 1980s and early 90s hospitals had to set up charitable fundraising trusts for bits of medical equipment because the tory government reduced funding to the NHS to absolute basics.
During the 13 years of the labour government funding was substantially increased and hospitals were able to afford all the equipment they needed. But many of these charitable trusts still existed and many were still receiving donations for causes they had long since met.
The labour government were considering introducing rules that would mean that if a hospital was given donations (and some of these were legacies left in wills years earlier) for items that had been provided by government money then the donation would go into the overall NHS pot to be used for wider purposes.
However this was never introduced due to charity commission rules that state that money donated for a charitable purpose can only be used for that purpose. This means that their are some hospitals receiving donations for equipment that they don't need but that are unable to use the donation for any other purpose.
Bonkers.
However, be assured that if the cancer unit at your local hospital is actually needed then your donation will go towards it. If it isn't needed your wasting your money.