I have a garage which one side is about 2 foot lower than the ground level. I put my Asgard bike shed on this higher ground and now water is leaking into the garage. Is there anything I can do?

Can’t see how putting something on the ground would affect what was previously a water-tight garage. Did you clout the gutter or something when erecting this shed?

So it was dry before the Asgard arrived? Put the Asgard in the garage then? I suspect we don’t have quite enough info to help.

Sorry, yes was dry. It is a prefab concentrate garage and the water is now seeping in between where two panels join. Water seems to be pooling around shed, which I put on paving slabs

Sounds like you need a fall on the slabs away from the garage

Ok makes sense. Would a trench with gravel help?

Yes, potentially, with some heavy duty polythene sheet (dpm) up against the concrete walls of the garage so the water in the gravel goes down and not into the garage.
You should try to see if you can see what happens in very heavy rain first.

It’ll get wet, I expect.

A gravel filled trench may help as long as water can drain out. They can actually make things worse if the water pools in there as it won’t readily evaporate. Better to arrange the fall on the slabs and the draining of the shed and garage roof so the water flows away