I have discovered CAR166 which authorises straight in approaches, joining on cross wind, down wind and on base
Yes, but as the previous couple of posts have stated, I think it's important to reiterate, JOINING BASE IS NOT A STANDARD PROCEDURE.
While the AIP states the recommended join procedures are mid-field x-wind and downwind (yes, straight in is an option), as long as the old rule of three legs minimum is followed you are legal.
The benefit of following recommended procedures is that there are only two points in the circuit where you would expect to see aircraft joining the circuit.
If everyone actually follows these recommendations (instead of doing everything but, just because they can
) there is a lot less scope for conflict. Doesn't mean you can drop lookouts though.
Just ask my student the other week when an early join on DW missed us by about 20 metres. No radio heard, just my insistence on a pre-downwind lookout that meant we spotted him in time (barely).
Vertical avoidance (yep, that pretty much describes the attitude attained) and an incident report followed.