Ok, I went off the deep end and answered too quickly. Let's try this; Forget gravity altogether. The measurements made were of the actual acceleration due to UA, not gravity. Of course all the variables have been accounted for and everything was done in a laboratory setting. The problem is that these laboratories are located all over the world and not just at the poles. Under the UA theory you can't tolerate too much of any variance in acceleration world wide or the earth would fold in on itself. Of course that isn't what has been measured. If you want to play the 'dark matter' card then that can be measured as well. Anything that has the power to accelerate a mass can be measured. I don't think anyone has seen any anomalous effects in this regard.
Roughly correct, but strictly speaking the data simply measures observed acceleration at different points in the UK (and the world). Perhaps I shouldn't have included the adjustments, since those require an element of theory.
The question is how to explain the functional relationship between observed acceleration and latitude. Globe-earth theory is the simplest. UA on its own doesn't work, given its basis in the earth's being approximately a flat and rigid plane. So we need an addition to UA, namely some unknown force, perhaps Dark Energy, which acts increasingly as objects approach the poles. Or leprechauns.
The problem with the Dark Energy hypothesis is it requires the very phenomenon that UA was designed to avoid, namely action at a distance. If we accept that, why not ditch UA altogether and make Dark Energy explain everything? Or why not just call it 'gravity'?