Can anybody recommend reputable makes and seller(s)?
Application is a small pocket torch, not a power bank or vaping, so I don't need high current, or high capacity - 3000mAh ± would be fine.
What about a connection from the gate to the tractor shed, wired or wireless (from what you've said either would be feasible) and simply have a loud bell or other sounder there which you can hear from the house?