Just a follow up.
Been on my new (to me) 4rt for the last 3 weekends. Starting to feel at home on it, much more so than the Beta I had before. The bike feels heavier, but more predictable and more planted. I love the throttle response, im still a bit jerky on the clutch, but im sure I can iron that out in time. Its already on the bench for repair having fallen foul of the well known fuel pump issue, whether the seller knew this or not, or whether I've just got unlucky is still up for debate. I've got a new Quantum pump to go on and will do oil, filter, gb oil etc.
Overall, really pleased with my purchase. Thanks to everyone that helped out.