I've just had a look at it and it looks cosmetically rough. No experience of Narwhal ribs, but with a 25hp it's not going exactly going to set the heather alight. Really you'd want 40hp on there.
With the market the way it is, then prices have increased. £2,400 is still a tidy sum for your fist boat so walk away if things don't add up.
As it's had a retube, and only 5 years old, any paperwork as to who did it? Any lifting of the hypalon around the hull?
Engine, then you want to see it running. The fact it's not in its manufacturer colours is a crying shame and whoever painted needs shaking. You may be able to pick up a used cowl as painting and decals aren't cheap.
I suspect with covid restrictions the current owner is tired of it. Why are they selling, upgrade?
If you are looking to repower down the line, and assuming there's a manufacturer plate on the transom, then check out the maximum transom rating and engine weight. Clyde Outboards have a Mariner 40hp.
https://www.clyde-outboard-services....tboard-engines
There's still money in the Suzuki 25hp 4-stroke, but will need to be tidied up to get top dollar.