Update
Hi everyone, and thanks to all who replied to my original post.
To give a quick update - I landed in Amsterdam last week and headed south from Haarlem to Hoek van Holland, where I caught the ferry to England. Of course the Dutch bike facilities were great, though less exciting as you get further south. Lots of Stop-and-Go in the (unavoidable) cities, and navigation was difficult, even with a good map. Mostly just used the sun to hold my heading somewhere close to South between stumbling across the bicycle direction signs.
Now in Cambridge after riding about 55 miles from Colchester today on the Lonely Planet "Cycling in Britain" route. I wouldn't exactly call the traffic terrifying, but I'm also pretty sure that riding in this level of traffic isn't my idea of recreation. Thinking of going next to the Sea-to-Sea, as it sounds like a pretty well-established largely off-road route. Then maybe to Denmark, unless some other rides in the UK turn up that are more to my liking i.e. off-road or very quiet roads. Might hit a bike shop tomorrow for some advice and maps, and obviously would appreciate any new advice from you all as well.
