spoc, is your Competition a Carlton? I ask because I have a (1973 I believe) Raleigh Carlton International frame. The lugs were pinstriped and were an unusual Nervex pattern. The rest looked like your bike. Tire clearances for 700c rims are huge. Big 35c Paselas have a tone of room around them. The chainstays have unusual butting, necking down substantially and very visibly right behind the BB. Looks like yours do the same thing. I've been told that chianstays were specially drawn for Raleigh by Reynolds in the '50s for a more compliant rear end for touring. My bike is a superstar for a non-suspension frame on rough roads.

One "feature" my bike had that I hope yours doesn't: Mine missed a step in assembly. Seems the lugs were perhaps tacked but not brazed. I had my framebuilder strip and examine it. He ended up flowing a lot of braze into more than half the lugs. I"m guessing mine was a Friday bike and lunch was spent at the pub. Good thing is the paint was done well and flowed fully into the gaps.

Ben