... working in a polling station a... get involved in counts ....
A likely story.
The two scenarios are different.
One is in the actual polling area, the other is in a secure, usually separate room/building, where polling slips are accumulated from multiple polling stations.
In the polling station, you deal directly with the public.
In the counting house,the public are severely restricted, and only official observers, (candidates reps), are allowed anywhere near the tables, usually behind a barrier.
When you apply, you usually have a choice of working in the polling station, dealing with the public, or in the counting house, dealing only with officials, because the two venues are different, and in some areas many miles apart. It would be difficult for Polling Station officers to also be counting clerks, due to the probable length of the combined duty, and the distance between the two venues. The Returning Officer can request a police escort from the polling station to the counting house, so votes will invariably travel quicker than staff commuting between the two venues. Counting staff are expected to be in position, briefed and equipped before the arrival of the first ballot boxes.
Counters are not allowed to interact with the public, who will be kept at a distance., nor the observers.