It looks like new mounting brackets with slightly different fixing hole positions may be needed to move the whole frame back a few mm. The rear one may need modifying in length.
Nor sure where you would source them, but these, apparently in polished stainless steel, look good to me (can't say of course what exact shape/size you would need):
https://www.ebay.co.uk/itm/154852392639 and
https://www.ebay.co.uk/itm/154852398128
