That’s rubbish, sounds like you got a jobsworth guard. I work as a driver and this sort of thing is embarrassing. Guidelines definitely do allow the guards to use discretion, I’m not sure of the exact wording and we as drivers are not trained in any ‘retail’ stuff but most trains have at least (physical) room dotted about for five or six, depending on wheelchair space occupation etc. What really boils my wee is that every day dozens of little toerags crowd onto trains together with their ‘accessory’ bmxs, they’re slowly stuffing it up for the rest of us. Myself and my guard had twelve of these little darlings turn up at one station this time last year, we told them we would take six of them and for our efforts then got six mobile phones thrust at us with whining parents on the other end.
As a suggestion perhaps try writing in, if you feel the train was quiet (can’t see it being busy up there) and you should have been afforded the benefit of the discretion at least the guard in question might get his/her ear bent by their manager and be a bit more lenient in future. We can hope. Leeds and Skipton guards (who most often work the route) are renowned as jobsworths though so it might be a drop in the ocean.