Was my School's both Senior Champion & Open Champion, two years' in a row.
I take it by 'over arm' you mean Freestyle & not Butterfly?
These awards were for Freestyle, Breastroke & Backstroke. Weren't allowed 'Butterfly' as too 'manly'! But I could do it very well.
Held a 50m Breastroke record which I set at 14. It took another 18 years until it was broken, & then by only one-tenth of a second!
Yes, I was an excellent sprinter-swimmer, not long distance.
Still enjoy swimming & next Summer might try for a place in Masters' Games! One can still dream!