Are there any ways in which the arty can be used effectively and tactically even as a faction different to the royal artillery?
Radio triangulation - Commando Tree.
Setting them up in distant 3 places is difficult but worth its price when Wehrmacht is building their late game super duper cheaper uber vet 3 units. Its great for spotting Snipers, Paks and Stormtroopers, not allowing Germans to repair their tanks close to the battlefield. Not only will you know where to drop shells but also how (witch way) to set your tanks (Hull down maybe) if theres any attack mounted by the Germans. I belive British armor force (without infantry - independent operations) is the most tactical challanging ingame (slow cross country speed, weak armor, Cromwell CT usage - not just causing traffic jams, very different gun stats, limited time on Flank speed...) Radio Triang helps you use the right formation to repel the enemy.
Theres off course the Captain victor arti too. Good when you can get close to the enemy without exchanging shots. Its great when your enemy base is outside the 25lbs range but you can get your Captain close it and drop some shells on reinforcing units. And then meybe some Officer or Commando arti too.
) Some free shells
With secured resources (Brits should never have more than 1 truck on fuel - becouse they dont need it that much) and with Radio triangulation detectors properly set up + 1 Howitzer build it takes 5 minutes to to finish off a defensive WH
25lbs should only be build 25 lbs when your oponent starts plaing very defensive. Unless you see an 88 you should never build 25lbs vs PE. Im not sure about the efectivness of arti vs Nashorns (reward unit).