Fully aware of this. Waited until I was about to set off to tell them what the law actually is. Didn't bother with the pedal and rear reflectors bit though, didn't wanna be too smarmy.
Just had city police pull me over at Liverpool Street for riding brakeless. Pretty annoying they know about that and actively pull people over for it but then say that a front brake and a freewheel is legal, numpties.
Fortunately I dodged a ticket which would've been £50.
.