Why do you ask ?
Is a road bike not retro enough otherwise ?
No offence meant , just curious as to your reasoning .
Just how many 50s bikes do you think are out there . Working . Owned by people on this forum . Period correct too I presume ?
And what of the members who have built lovely bikes , not 50s , and not British ?
Do they have to wait for a 70s Italian rBotM , or whatever period or country of origin their bike falls into before they proudly exhibit the result of their work ?
Food for thought .