Daresay a few of us saw this very large John & Yoko on Antiques Roadshow the other night.
https://www.express.co.uk/showbiz/tv-radio/1172796/Antiques-Roadsho...
I cannot get iPlayer over here but if anyone can upload the video even better.
Don't think you're likely to see a larger example - seems almost too large to be true but I guess it must be "right".
At least Hilary Kay didn't do the usual AR under-valuing thing - £35k-£40k might even be a bit full.
One thing that did bother me is that the item seems to be under sticky-back plastic. I presume that would have been mentioned though.