Primary position

There is nowhere near the amount of cyclists in Birmingham and cars have no idea how to treat us but I rarely encounter aggression such as this yet in London where bikes are so abundant now, I encounter aggression quite often...it's quite interesting. I feel like when I move to London/if I teach here I will have to adapt how I teach to take into consideration alot of differences.

Your experience, of suddenly noticing something that you hadn't anticipated, is perfectly normal in London. I haven't cycled much in Birmingham, but I would say that yes, there is a definite difference. I would say that in London I would tend to ride in the primary position more, although that is probably partly because in Birmingham I was sightseeing. I did ride halfway around the inner ring road in Birmingham (missed out the southern half because I turned off too early), mostly in primary, especially in the tunnels, but there was only very light traffic. Despite a lot of fairly appalling traffic engineering, it was all very easy (and distances around the inner city were so short!).

In London, activity levels are so high, even in a suburb on the edge of Inner London such as Hackney, that you have to remain alert constantly. If you 'nod off', you'll probably end up being surprised. I think this is a major cause of stress for people and applies across all modes, even walking. Places with a slower pace of life are probably a lot healthier than London, I think.

My friend who'd ridden ahead came back to see what was going on and banged on his window, the guy jumped out the van and started screaming "What the fuck is your problem?" at me. I was shell shocked and didn't say anything. The two guys began to argue and the driver tried to headbutt my friend(!) before driving off. My friend then started shouting at me saying I should NEVER ride in the secondary position and I began to cry (out of anger I suppose) because well it's my goddamn job to teach people how to ride safely on the road!

snip

Further to the above incident, I then spent the rest of the day questioning myself, I always ride in the primary position when it's safe to do so but feel like I should also act sensibly and not block the roads when I'm going slower. I teach the syllabus exactly as it says on this topic but it seems like different instructors have different opinions on this...I know some instructors who NEVER take up primary except when turning and others who are adamant that you should all the time.

Well, your friend (is he an instructor, too?) is obviously wrong if he meant to articulate an inflexible and dogmatic position. Whether or not you take up the primary position depends on your risk assessment of the individual situation. As for those instructors who choose to take the primary position rarely, I would say that their stance would increase risk to them in a good number of other situations (pinch points, etc.), and that they shouldn't teach what they say, but that their own private riding style is really up to them.

Dogmatism about the primary position is something that most people who don't understand cycle training (well) slip into really easily.