The PHE report measures both antibodies from natural immunity, and antibodies from (vaccine or natural infection or both). (They don't have a vaccine-only measure.) The former is in the 20% range, depending on age. The latter is in the 97%+ range, again depending on age, reaching essentially 100% for older people.
The big caveat is that the sample population consists of blood donors, which may or may not be representative of the overall population.