If it wasn't so funny it would be exhausting just watching the antics of four fabulously capable actors turning the stage into a ridiculously broad range of settings with a few well-chosen and well-made versatile props.
The speed of their transitions was an essential part of the continuity.
Trains and bedrooms, offices and lobbies, cars and aircraft, moors and mansions, all had to appear in seconds.
Add to that the dozens of characters in the play, the multitude of doors and windows, corridors and platforms and the result was a highly entertaining workout of mammoth proportions.
Credit to the cast for striking the right level of humour that acknowledged the integrity of the script, and for their serious approach to what is insanely funny and was therefore even funnier.