I saw this same steam locomotive a few weeks back down in the West Country, see....
https://www.ontheupfast.com/p/21936chg/30036747383/x45699-galatea-45627-sierra-leone but seeing it on what would have been more of its traditionally associated natural home got me out early on this miserable and grey March morning. 45699 'Galatea' masquerading as 45627 'Sierra Leone' races along the down slow line at Old Linslade just north of Leighton Buzzard. It was leading the 1Z33 'Cheshireman' charter from Euston to Chester where it arrived just one minute late. Notice that there are a number of other enthusiasts out who are equally as silly as me to witness the event.