If you do end up getting checked out on tailwheel it should only be a quick checkout back in the UK to get signed off. This is of course assuming you fly a similar type to the one you flew in the States, if you do say Piper Cub then try to check out on a Chippie it will take you slightly longer, though if well taught even this should not take much more than an hour or two. Probably not worth a special trip to the States for this as most peope will be OK after 5 hours or so (some more, some less of course).