Thank you to Bob for the improved photo and also to Gameswat for the excellent link to the Cox's site. The picture does pose a question, where do the used cups go? On the usual size machine there is a recessed tray behind the pediment. On the Ell's machine on the small size a galleried top to place used cups and on the similar size to the standard Cox machine brass tubes inside the machine and the cups replaced in the top. I bought a tall Ell's machine of a similar size to the Cox machine from the Elephant House auction in 2017. Until this I had no idea this larger size was made. I expect the Cox's machine also held £40 of change being 27 x £1 and 26 x 10/-.
Below is a picture of my machine. There are hooks on either side and holes where screws would have held a base plate, suggesting that originally there would have been a return tube on either side which could be removed and swapped for the empty tube in the machine when all change had been given. Is it possible this was how the tall Cox Machine worked?