Look what I just got in the post

Depends what the average density of Haribo is, this bag weighs about 1300g, so there's only 8 and a half kilos of weight available for haribo and packaging.

And my clothing, helmet, shoes etc.

Luckily, my bike is about 8.5kg and the limit for a bike bag is 30kg, so I could pad my bike out with Haribo, or whatever soft delicacy I can usefully import from Poland.

no.
separate packages from wiggle will get you more haribos.
haribos from poland are the same as everywhere else.

except cheaper.