What time approximately does the sun come up and set in late April- May in England? What time does it get dark? Does it vary much from the north to the south?

There are hundreds of sites that will tell you this, if you do a quick search on google.
Yes, it does vary from north to south.
Glasgow (yes, I know that's Scotland): Picking Thursday 26th April totally at random the sun rose at 05:45 and went down again at 20:42. A month later the times were 04:46 and 21:39.
Picking London down in the South (yes, that is England): For the same dates in April it was 05:42 to 20:13 whilst in May the times were 04:54 and 20:59.
So yeah, Glasgow tends to enjoy an extra half hour to hour of sunlight.

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<hr>So yeah, Glasgow tends to enjoy an extra half hour to hour of sunlight.<hr></blockquote>
I think you mean daylight and thats streching the definitiosn :-) Don't think I've ever seen teh sun in Glasgow :-)
World Clock is a great source for this information, will provide it for all over the world as well.
Cheers