The 850GS has gone so I have the following up for sale - prices include mainland UK postage. Both fit either F750GS/850Gs and the engine guard fits the GSA too:
Wunderlich stainless steel polished silver engine bars (lower). Retail is £235, only on bike for a few months, used maybe 5 times. Perfect condition. £160 posted. This is the link: https://www.nippynormans.com/f750gs850gs/wunderlich-engine-bars-f750gs850gs-stainless
BMW OEM aluminium bash plate - provides extra protection for headers and sump. Cost £202, immaculate condition. £145 posted
Photos available on request.