parabolic (GB springs) - u-bolt size

I'm fitting rear parabolic springs from GB Springs to my Series 2A petrol 88".

The u-bolts GB Springs sent me are a bit thicker than standard ones, so the locking tabs I ordered by part number to match need drilling out a bit or I need to order correct ones.

How do I order nyloc u-bolt nuts and locking tabs for these larger u-bolts? Do I order by heavy duty part number, 1-ton, etc. what are they? Do all parabolic springs need to use stronger u-bolts? I though u-bolt size was only a function of the vehicle weight.

With the nyloc nuts you do not need the locking tabs.

Music to my ears. And exactly why they sent me nyloc nuts and no locking tabs. Cheers Blackburn.

(Goes out to garage to see if there are nyloc nuts AND tabs on the front.. )