This was OK but when I came to remove the old belts and especially that outer hip mount, I found a problem. Despite being a late vehicle (1990 G reg) the bolts were very close to seized in the captive nuts and it was obvious that the panel was flexing under the spanner loading. After eventually successfully removing the bolts I decided to tidy up underneath.
The rubberised factory underseal had broken away from around the end of the bolt and was clearly not adhered to the panel around the nut. So, I decided I would cut away the underseal back to a point where it was still adhered - up to two inches from the bolt in places. This exposed significant rust which I attacked with the rotary wire brush and that left the situation you see in the pictures below.
On the right hand side:-



and on the left side:-



I am now very pleased about the change of mount position. However, is does beg the question just what state apparently-healthy belt mounts are really in. Would these have held in any significant impact? I rather doubt it.
What state are yours in?