Thanks for the suggestions, Timethief, but the suggested articles don't solve the problems. I've been nosing around the forums but can't find answers there, either. Does the silence from the more technical members of the community maybe shows that I've hit on some insoluble bugs in WordPress and/or Sandbox?
It's the dateline bug that really annoys me. I've used padding to narrow the central text column of Sandbox, to make it more reader-friendly. This means padding all the elements - no problem in Firefox. But in IE, everything lines up except the date.
The favoured solution in the forums seems to be - use the Firefox browser. Well, I do - but a load of my readers probably don't. They will tend to be literary types, probably not very techie, and happy to use the browser that came bundled with the machine. It's a pity if WordPress can't make the blogs look decent for them.