Les Desser wrote:
Can I stop to pick up a friend I spot along a double red line Red Route?

I was going to write "no", but it appears that the answer is,
unbelievably, "yes".

http://www.highwaycode.gov.uk/22.htm

Scroll down to para. 215. A "red route" is an urban clearway.

Ditto for a bus stop?

I don't believe so, unless you happen to be driving a bus.

Neil