While doing some advance planning I just noticed that all Great Western Railways Ranger (1 day) and Rover (more than 1 day) tickets can now be purchased on line.
While the Cornwall and Devon day tickets (especially) offer superb value (more so with a railcard) do not, on any account, buy on line. The only delivery option is next day by mail at an add on cost of £7.50.
All such tickets can be issued at any railway station in the country (Yes you could buy a Cornwall Day Ranger ahead of time at Inverness if you wanted to!!), and as far in advance as you wish; or on train if joining at an unstaffed station- at no extra charge.
So there is no need to fall for paying anything (let alone so much) to be mailed out.