Marinyork,
I'm not planning to carry on with this discussion much longer, other than to say that 25+ years in broadcast engineering, much in sound some in transmission and systems, might have left me knowing just a little.
"What you don't seem to grasp is that some of the more difficult regions to go digital were picked last " You are wrong. The order of change is just a function of planning the switchover assuming London last because its biggest by population so any bugs get ironed out before going there.
Wales (next year) is by far the most difficult region to do, with the most potential problems with Scotland, not sure when, next most difficult. The North East which I believe is your area is relatively simple (much simpler than the South West). The West is supposed to be the simplest so my guess is we'll have the biggest problems.
"Anecdotal evidence suggests that digital won't work with perhaps as much as a majority of indoor aerials". Information is being collected from the South West. Overall , I'm told, its looking very 50/50 wins to losses for room aerials. For loft aerials the number which don't work when they did before is minimal (I haven't seen the report which will contain this yet).
"when you have little knowledge of the how the coverage predictors work" I used to teach this!
"To deny so is village idiot understanding of digital and distribution systems" It's now a minor part of what I do, but I still design them!
"Places like London will have considerably more of a headache" London has challenging problems owing mainly to the effects of buildings. That's why analogue is poor in many places, particularly with ghosting problems. The type of transmission system (OFDM) gives digital some resistance to multipath (ghosting as was) interference, but it falls over fast at its limit. My guess is that there will be a greater problem in London than in most places, but still only very small.
"an optimised system for digital is not the same as an optimised one for analogue" Provided the transmitters themselves meet the specifications there's very little differece.
"I've also highlighted a sentance that I think is important but which you clearly don't think is so" It isn't. The numbers affected are tiny, and experiments with typical aerials in use (done in the real world with real signals) have proved that they can cope. I'll check if it's being done if I need to, but I was told that a small compensating increase in power was possible at all affected sites.
"you have a poor understanding of the engineering issues" I would respectfully suggest that it's very much the other way round. The "biggies" have all been considered and addressed, to the extent that there aren't expected to be any which affect viewers.
"If we lived in a perfect world where everybody had high quality roof top aerials and kept their cabling in good nick digital would be fantastic. People can't be arsed with that, so there will be a few problems." That was the biggest worry when the switchover was planned. Experience in Whitehaven, and then in the South West has been that because people "get the aerial man in" when the picture gets bad, there are far less than expected which won't work.
"As for RF modulators" The boxes with them are available, Virgin have nothing to do with it except where they provide the receiving equipment, and dealing with their customers is an issue for them only. The boxes just work, the same as the ordinary boxes do, but cost a bit more.
"As for comparing satellite to terrestrial!" For most people the terrestrial digital changeover is easier - only one thing to add, and it's indoors.
"PS you forgot to mention the QAM change too" No. The experimental result is that with the higher power, and the syatem calculated and optimised for QUAM 64 the coverage, protection and robustness requirements are all met.
As I say I don't intend to continue this as it'll go nowhere, however respond if you wish.
The proof of the pudding .... We'll know in 4 years. The Germans are well ahead of us, with all information published, much in English as well. If you're interested take a look.
Edit: I assumed you meant the technical performance of 64QAM. There is of course an issue which can't be resolved. Some of the On Digital boxes, inherited by users when ITV digital collapsed, won't go on getting anything. They're old and weren't paid for anyway.
There's another issue, more real than any to do with switchover, and that's what happens next. If there's going to be significant terrestrial HD it's very likely that the coding will have to change rendering all the boxes we've just bought useless, and all the new digital TVs in need of a set top box ......
don't you dare quote it back at me and pretend you brought it up first. I'm also a bit annoyed that you keep on regurgitating things I've already written for example on indoor aerials and London and then saying oh I disagree but I will write something that actually agrees. 
