Tesla, I am not intending to retire anytime too soon, unless I win the €millions, and I am likely to be buying in Scotland - somewhere north of Pitlochry, and probably north of the Great Glen (Inverness-Fort William for the uninitiated). Northumberland is still a possibility too. My wife and I were both brought up there.
Very interesting that you should mention cash rates. In my time as a bureaucrat I had several years of responsibility for looking after the cash flow of a department or entity. This often meant managing several millions of very short term spare cash of the local currency - just until the cheques hit the bank. The best rates available were always the overnight or 24 hours notice rates through the major banks. I once, only once, in Australia, managed 20% (p.a.) on either $A3m for 4 days, or $A4m for 3 days, I forget which, but frequently obtained 18 and 19%. Leaving the cash in the bank would have earned nothing for my employer. I know that most people who post here are of the opinion that bureaucrats do not have the intelligence to think of such things, but they are wrong.
If I had a minimum of £1m available I would make it my business to use the Treasury departments of the mainstream banks (not Iceland or BCCI - that was their credit rating I think, not their name) to earn my income. Make the decision every morning, 11am cut-off for some, and noon for others, whether to stay put or move. An extra 1% on a million is 27.40 a day, but security comes first. It is only a few seconds of thought and calculation to make the decision whether to stay put or move elsewhere. After a while they phone you to ask whether you have spare cash for anywhere from overnight to a couple of weeks. When they need you the rates increase slightly.