New Supra - Problems Changing Gears..

[meko]

ok...

i picked up an L reg Supra today (12 hours ago), none turbo model. I took it for a test drive on Sunday and it was fine, i picked it up today and it was fine driving home.

At half 6 i got in the car to see the other half, started the ignition and it wouldn't go into gear. If i turn the ignition off it will go into all gears perfectly but as soon as i turn the ignition on it either won't go in or needs banging in. If i put it into reverse with the ignition off it will reverse on its own as though its an automatic.

The sensible part of me is saying it could be the clutch but then when it goes into gear fine when the ignition is off, would that affect the clutch?

is it possible that when the engine starts up its knocking something out of place so it's not 'catching' the gears?

As i bought it sold as seen and it was fine when test driving and driving it home i've a feeling i could be screwed on taking it back for a refund as it was a private sale.

any ideas?