Please don't take this the wrong way Kate, because I'm not trying to suggest you can't read or whatever. Just a wee note:
Both my gran and I got a letter saying the same thing (pretty much) and since we live relatively close then I though I'd mention it.
My gran, panicking about not getting her tea and lunch etc went out and bought a wee gas cooker thing to heat things up on, and dug out the radio since she wasn't ging to have any TV or anything. UNTIL, I pointed out to her that, like mine, the letter did not say it would be off between 8am and 4pm, but rather it said that it would be off for a 10 minute period between 8am and 4am.
Like I said, please don't take this the wrong way, just thoguht it was worth mentioning.