Good evening,
My recently deceased Uncle told me the Panda was his regimental mascot, he was in the 5th Royal Inniskilling Dragoon Guards, if this helps you at all.
I think he was pulling your leg with that one. Only 6 types of animal have ever been official mascots, upkeep paid by the army. Unofficial mascots known as regt'l pets upkeep paid by the regt, have never included panda's to my knowledge. The chinese would never sanction it.
Also, only 2 cavalry regt's have mascots, the Scots Dragoon Guards and the Queens Royal Hussars. They are both drum horses.
John915