Help with identifying plant

Personally I go along with the dead Broom idea.( Cytisus scoparius)

They hate being disturbed and dont transplant well. Very often die.
Was it originally in the neighbours garden, and they potted it up?
I'm not sure it makes a good pot plant either, even if grown in a pot from the outset.

Lets face it, snails are everywhere this "summer", so I'm not thinking they are unusual.
Laburnum is another plant that attracts snails and they can often be found high up in the trees even in dry summers.
Not sure but I know broom is closely related.

 

I agree Pete, I noticed the leaf shape of Laburnum is very similar to that of the Cytisus broom... (Cytisus is now called Genista apparenty?)