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In brief, Ringo sold it to Sheik Zayed bin Sultan al-Nahyan in 1988, who proceeded to spend a, frankly, atrocious amount of wherewithal on gutting the interior, adding a whole new wing, constructing a bomb-proof swimming pool (I shit ye not), and generally doing all the things that one is not really supposed to do to a Grade II listed building. (The High Court had to step in to stop him going further, apparently.)
Anyway, above - the house in 1969, a few months before John bought it, and the same view now: the area under the terrace has been turned into a room. Speaking of which, here's how the Imagine errr..."turf" (as featured in the video) looks these days:
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...and how it looked in the titular film:
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The balcony, where the final pictures of the four of them together were taken, is long gone; that portion of the house has been turned into a new wing, because 50 rooms (or whatever it was) isn't really enough, is it? Clearly not:
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An internal (fairly obviously, though nothing would surprise me) staircase (the camel photo possibly not there in the Lennon/Starr era)(nor anything else):
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Finally, that bomb-proof swimming pool, together with the one that used to be there. An outdoor pool is generally regarded as a sign of wealth in the UK, but the old one looks positively spartan compared to the cash-fest that's there now. One reaches it, naturally, via an underground tunnel:
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The Sheik died a few years back, and Tittenhurst now stands empty for much of the year, though there is a small army guarding the perimeter to ensure scum like me don't get a shufti.
Many thanks to JammyEye for the pics.