On the rear dropout there should be a stamped code, the year can be worked out from this. If you could put up a view of the front lugs and the seat lug it might help. Also whats the seat pin diameter. Thanks Terry
Are you sure about the first digit, 'O' makes it 1947, which it clearly isn't, could it be a 'U'. My guess at this point, assuming they are nervex lugs which look a possible from this distance, the pump braze ons on the top tube, and twin shifter braze ons it could be a 1954 - 1958 Sun Wasp. Thanks Terry