Enflow Bath mixer taps (drippy)

got a leaky tap (seems to be the hot water that's the worst). just wondering if there is anyway of finding out if its metric or imperial without taking it apart?
got a feeling they are imperial as its quite a dated bath setup (pink enamel coated tub) which makes me think 1970s....
cant find anything about Enflow anywhere. I just bought a set of metric and imperial washers, but to be honest, i dont know what to expect after i take off the tap cover....

ive not seen metric washers 3/8 1/2 and 3/4 inch covers everything

ta, i took the plunge and took it apart. actually found some 1/2" washers lying around and they fit magic problem solved. did snap off the water cut off tap head though....that was an interesting one to solve...