In the historical, context Lloyd is correct on beaters but I can’t speak for pickers up. I have seen and still experience, both ends of the spectrum. The local, farm or small syndicate where you shot Saturdays to the large commercial shoot where It is weekdays.
In the former I was happy to have any beater who could walk in a vaguely straight line, without holding hands and make a little noise. They were paid in cash at the end of the day. Money collected from the guns and distributed at about thirty quid for the day.
On the commercial shoot you have an employment contract, are clocked in each day electronically and paid monthly after deductions for tax. Holiday pay is added at the end of the season. You have to be a very competent picker up as there is a lot at stake but even so put an extra couple of birds in the bag and you have covered your cost and more. That just about covers my travel and dog expenses for the year and as I do it for the love of it I have no problem with that.
If we think about the dreaded Covid the formal approach is probably a must for at least this season so you know who has been in contact with who. As to money you probably get what you pay for and remember in rural areas beating might be the only employment for some for the whole year.