In all reality you'll be fine in the UK, and worried about nothing. I went there with mag stripe only cards, and I had no trouble at all.
Also Visa and MasterCard have mandated that those kiosks you complain about are required to listen to the CVMs on EVERY card, which means yes, your Chip & Sig will work fine. There are also numerous threads on FlyerTalk confirming that C&S cards have recently started to work just fine in these unmanned kiosks.
By the way; the kiosks and card terminals still have a regular MSR in them too, because of a few reasons:
-Prepaid gift cards are not Chip & PIN, because of their nature it's too expensive.
-Store gift cards
-Fallback if the chip is broken, the machine will still read the mag stripe.
If you really are concerned about C&S, insert the chip the wrong way a few times, and the machine will say "Swipe Card"- or "Insert and remove card quickly"- forcing the machine to do a mag stripe fallback.
Also side note, if you have your cards in Apple Pay, it works internationally with US cards. Use that to save some trouble.