Plant identification

[toomuchtooold]

Hello all - among the various delights of my 1980s throwback garden are 5 of these bushes. Does anyone know what they are?

I'm not an expert but I thought any reply is better than none!
I think it might be Hibiscus syriacus.

Thank you! Have just google image searched for hibiscus in winter and the seed pods and the shape of the flower look exactly right.