Reviewed an application from a pair of identical twins today. Fascinating. They were applying as a unit. Everything on their (one) application form applied to both of them (except, obviously, their first names; plus one small element of their employment history).
Unfortunately, they were applying for central London and didn't have bike licences. Plus nearly all our work is solo work and I did get the distinct impression they were at their best when working together.
But they'd do well if they set up on their own. Assuming they are good, everyone who used them would talk about it to their friends.