There's one just like this near me (in East Sussex) - SE Sport, silver, spoiler and rubbing strips, 51 plate - everything.
It (they) probably started life as a dealer demo at launch kitted out with dealer-fit accessories, such as the spoiler and rubbing strips. 51 plate is very early in the lifecycle as sales started in early 2002.
The spoilers were always extra a dealer-fit accessory and quite popular too.
SE Sport had a short run as in late 2004 the Sport (bodykit, climate control, black/grey interior) replaced it, so not that many around.