AOC needed to do Flight Instructing?
 

Can a flight instructor give lessons, say for a PPL in an R22 in the UK without needing to obtain an Air Operations Certificate?

hey man its far more liberal than that,

for a start no AOC required. then you have 3 levels of training organisation.

at the top you have the Flight Training Organisation (FTO), they offer training for professional and private licences and ratings, they need to be approved, for ab-initio, licence holders holders etc

next you have the Type rating training organisation (TRTO). they conduct type training for licence holders only. they need to be approved also.

then you have a Registered facility (RF), they can only conduct PPL training and crucially cannot do type conversions.
but heres the generous bit, all you have to do (apart from keep some records, use suitable qualified instructors, buy some exams etc) is to send off a form which basically says " I are a registered facility" and thats it your done you can teach PPLs !

What da ya reckon to that ?

You don't even need to buy exams. You can get them done at another facility. You will however need to devise a tech paper for the aircraft you are training on and submit it to the CAA. J