I just arrived in Portsmouth 5 days ago. I've never been to the UK before. I was on the continent for 2 months, cycle touring, camping and staying at youth hostels. Here are a few of my thoughts on cycling in England:

• Piloting on the left is a mind f**k after 50 plus years of doing it on the right. Complex intersections will test your faith . I am making progress, slowly but surely.
• I'm not a great planner, didn't really have to, but did ok on the continent. The EuroVelo cycle paths were signed pretty well for the most part with name and/or number. I got around without much drama with digital maps and apps. England just uses a generic cycle path sign that may or may not be the one you are trying to follow.
• People talk about the traffic in the south of England. I grew up in SoCal, traffic is no big deal. What is a big deal is the narrowness of the roads and the complete lack of shoulders. There will literally be no place to pull over, hedges right to the edge of the road, and you're doing 2 mph up a hill with a line of cars behind you. The drivers have been very good and afforded me plenty of room, but still, it is the craziest riding I have done in my life.
• I have limited experience but the Rhine River and Normandy (highly recommended, by the way) are littered with reasonably priced campgrounds for tent camping. England not so much. For the first time on my trip, in 2 months, I have resorted to wild camping. Fortunately southern England is rife with wonderful places (parks and large stands of trees) that you can duck into and set up camp for the evening.
• Food and libations in Germany and France were competitively priced with equivalent items in the U.S. But the beer, wine cheese and bread are to die for in Germany and France (had to give it 2 thumbs up). England is quite a bit more expensive (and the food is not quite as good), especially alcohol related products.
• Rush hour is very hectic and I would recommend not riding during those hours. Those quaint little lanes fill up quickly with cars in mid-afternoon to early evening.

Like I said I've only been here five days and barely scratched the surface. We'll see how it goes from here.
I am heading up north to Hadrian's Wall and hoping things get better.
I am writing this from the youth hostel (YHA) in Streatley-on-Thames. Nice little place, lots of charm, the people (hosts and guests) are very nice, would recommend.
Look in the YHA in the UK, they are fun, unique places for reasonably priced accommodations. Really a great way to meet other folks that are travelling.
So good luck on your UK adventure.