(UK) Found share certificates after Grandmother's death for company that has been twice sold since purchase. Are they still valid? How do we sell them?

We have found share certificates that were purchased in 1991 for ManWeb (UK Power company). I have since found out that Manweb was sold to Scottish Power in 1995, and there was a subsequent takeover bid in 2006 by a Spanish power company Iberdrola. I have no idea where to start about finding out if the shares are still valid or selling them.

Submitted March 19, 2017 at 07:06AM by noreallifeplease http://ift.tt/2mIVm9J