right i,ll try again
if i remember correctly, when i welded in these plates i had a few mm over which i think came from the measurement 288mm,
so if you have your steering rack available make sure the rack fits into the support & that you can get the fixing bolts thru, i had to widen the slots a little & grind a bit off the edge of the supports to make it fit snugly.
hope thats better info than my first attemp,
andy