I'm sorry, we're going to need some clarification - I'm assuming, by 'golden chain', you mean Laburnum, but I don't know what's half yellow and half pink, and obviously, can't see the bark. Please add more information and a photograph of the problem if possible.

This sounds like x Laburnocytisus 'Adamii', which is a very strange hybrid between laburnum and broom. No idea about the bark, though.

Never heard of that, Landgirl, looked it up - unfortunate colour mix, I always think pink and yellow together is ghastly and try to avoid that combination at all costs... unless one of the colours is very delicate and pale.