A relative has an outside tap - about 25 years old. A modern hoselock
fitting is too big for it - and the supplied reducing bush is too small.

My local shop told me that there are only two sizes and the adaptor / full
size should be all that is needed. Clearly not.

Any suggestions? (other than changing the tap - I don't have the time or
inclination - such tasks at the house seem to escalate into major projects.)
Is there a further size version that I need to be seeking and am likely to
find?