Hi Casso that is not a cranesbill - I suspect none of your seed germinated. What you have in the foreground of your pot is a tree seedling - probably a prunus.

Thank you Moon grower. I haven't a clue where a tree seedling came from.

In the compost, dropped there by a bird or squirrel... we regularly find odd things growing in our seed pots!

Thank you. I'll pot it up and see what develops. We have laurel hedges both sides of the garden. I'm disappointed about the cranesbill seeds not germinating. I've grown other seeds before with no problems.

The leaves look a bit like the leaves on my magnolia. Could it be that Moongrower?. I remember poking some offshoots into a pot last year,

They don't look like magnolia leaves to me Casso, as I said probably prunus