started a while ago and getting slightly worse over the months.

anyone know what this could be?

I was thinking clutch as only happens in 1st gear and car generally feels like its not getting the power to the wheels??

Could be, I suppose, the thrust bearing trying to make a bid for freedom.

If accompanied by a knock from passenger footwell, rear gearbox mount.

But it's so hard to diagnose noises without being there, even videos.