So I've binged all six episodes and here's my conclusion.
Taking esteemed British actor Steven Toast to LA was clearly intended to generate a new angle for the jokes. But it's the American influence that is the series' greatest weakness.
You get the sense that the writers were so star-struck by the cameos they managed to secure - most of which are literally "phoning it in" - that the usual humour of Toast is completely disrupted. I won't spoil who appears in the show - but it's certainly impressive. Perhaps the producers have one eye on international sales?
Episode one is a waste, creating an un-Toast-like situation to force him to leave for the States.
Episode 2 is stuffed with American cameos and a complete failure.
However all is not lost.
Episode 3 loses the American cameos and is all the better because of it. Episode 4 and 5 return to the classic "Toast" format and are right up there with anything from London, while Episode 6 is a fitting climax to his adventure across the pond.
There may not have been any actual filming overseas because the two US stars that have more than a cameo only appear on one set. This is London masquerading as California, with a great cast of British actors and comedians masquerading as Americans.
Stick with it. It has some brilliant moments. But it doesn't reach the sustained peaks of Toast of London.