This has been covered pretty well on the US forum. Step 1 is to replace banjo bolt and crush washer, this will mostly likely not fix your issue…….
“My experience was similar to yours. They did the HG repair and all seemed well for a few weeks. However, after a long spirited drive I saw oil on the turbo banjo bolt. Initial repair was ensuring bolt was tight and replacing 2 washers. Once again under general driving no leak, but after some aggressive driving the leak was back. Dealer replaced oil return line and new washers. Within a few days it was back in the shop for oil leak. This time the replaced the timing cover and the leak appears to have stopped/been fixed. Some RS owners have had to have the HG replaced AGAIN.
Tech said that the early HG services (mine was in April) recall assembly procedure was changed adding sealant to some locations that previously hadn’t be included (don’t know where that spot is located, but suspect it is near timing chain cover. He also said there is an oil passage on the rear passenger side of the block, near the timing chain cover, where oil is used to control variable cam timing and that seems to be contributing to the leaks I’ve seen. He suspects that a combination of location, recall instructions and timing chain cover to block fit/sealant was causing the issue.”
Mine has this issue it goes in for second service next Friday and I have said I want it sorting during the service. I only think you can fully see it with the belly pan removed. I always have a good look around mine before and after service.
Mine went in for its 2nd service yesterday and they found I had this leak as well, I was half expecting it really after reading how common it is after the HG recall. No drama as they ordered the parts overnight and sorted it this morning.
2017 Nitrous Blue RS with every option except shell seats – no blue bolsters for me though.