Matching trailer to Indespension units

Hoping it's ok to post here, as it's kinda cars related.

I need to replace the Indespenion units on my trailer. The new ones all seem to be a standard size with mounting holes 76mm apart. Fair enough, but the plates on my trailer that the old, knackered, ones are attached too have mounting holes that are slight off those centres.

Any suggestions for the best way to mount the new units? Stikes me some options are:

1. Weld new plates on the trailer body, so they can be drilled with perfectly matching holes;
2. Drill out the exiting holes a bit, so they are oval-ish and should be able to accommodate the new units. I don't like this idea much as they could work lose in the bigger, oversized holes.
3. ???

Is there a better solution? A right or wrong way? After all, I don't want the suspection coming loose at 70mph on the motorway.

Thanks.