I was able to buy this SE1 from Tom / Reckless_Engineer on the mamod forum. I was on the lookout for one of these for quite a while already, so when this one came along for £110 I didn't hestitate too long to buy it.
I'm not too sure the paint on this engine is original, since there's no mamod decal on it anymore. The paint on the firebox looks a bit like someone sanded it down at some time.
I might do a full restoration on this engine in the future.