First gear vibration?

As the title reads ?!? Just a burst of a medium vibration when lifting to biting point. Any ideas? Just a top up /change of oil maybe??

I'd be looking towards your clutch rather than gearbox, how is it changing from other gears?

It's fine gear changes are ok, and I think it's definitely the box as there was a nice bit of gearbox oil pooling under the car!