It really should not be beyond the wit of man to have a standardised scanning system at the gate that relays the attendance data back to the visiting club.
Here's an "ideal world" idea.
When a STH is buying a ticket for an away game, instead of getting a printed ticket sent to them they could have the game uploaded onto their season ticket card, and beep it through at the away turnstile. Non-STH’s could get an “Away card” for the season that works in exactly the same way, whereby the away game is loaded onto it, and they beep their ticket through at the away ground accordingly. Then and only then are the loyalty points added. This way the whole system is streamlined, no waiting on tickets being delivered etc.
This would of course require some will on the part of all 20 PL clubs to incorporate such a scanning system, which is probably fanciful as they don’t really get anything out of it. Nice idea though, I reckons. Doesn't address the occasional away games at a tinpot lower league ground, but at least it would prevent instances happening like like night.
Not all away grounds would use the same system or scanners - so that wouldn't work.