I suspect we will never know. However, let's remember that this is a West Coast loco and it was going to be operated by a DBC crew and that's unusual. Back in time when Clan Line was a late substitute on a West Coast operation, the owners had a view about who the crew would be and an ex Southern man did the honours. Maybe West Coast was concerned about who would be in charge. When two different TOC's set of operational rules come together who can say what will pop up? But there again, maybe it was a last minute problem after the recent work on Tangmere. Who knows?