b+e on a pre 97 licence allows a vehicle upto 3,500kg pulling any weight trailer so long as the trainweight of the towing vehicle isnt exceeded . could be 12 ton trainweight with the right tow vehicle.
if you renew at 70yr old you should retain the b+e its the c1and c1+e they remove . and the d,s as well.
if they do remove b+e get right back to them .
thats why 5ers are ideal for over 70,s .big payloads and no medicals with the right outfit.