Pavement cyclists beware

Might try that. I have an aversion to major roads, but that doesn't sound too bad in theory. Thanks.

You have also got a point about walking the last bit, I'm just impatient and it would add about 5 minutes to my 20 minute ride..!

Why don't you get onto Liverpool Road from Copenhagen Street, and then go along Islington High Street? It sounds as if you work just to the west of the Angel junction, so this wouldn't be a big detour (it would add the traffic lights at the Liverpool Road/Upper Street/Islington High Street junction). It's not surprising that turning from Baron Street into Pentonville Road scares you, as this is, as you say, laid out for the one-way system--there is no concession in the layout here for contraflow entry. Alternatively, why not walk your bike along the footway for the last bit? It's not far.