Correct, riding two abreast is supported by the Highway Code. The CTC strongly advocates for riding two or three abreast to reduce the risk of dangerous overtaking by motor vehicles. I'm a keen cyclist and car enthusiast. Adding a few seconds journey time to minimise the chance of causing injury to a fellow human being seems perfectly acceptable to me.
Might be ok on a wide road but three abreast on a lot of B roads means you struggle to find enough width to pass safely. I prefer to give cyclists a good metre.
For a careful driver three abreast becomes a rolling road block.
We always pull in to single file and on a small country lane stop and get the car past, being run over once is enough.