It had a broken screen and was very battered.
I replaced the screen ( £6 Ebay) and it worked fine. ( Replacing the screen is easy and fun; instructions are all over the internet. )
The trouble is that thecharging socket does not engage unless it is held in with all my might, or strapped in with two zip ties ( which makes it impossible to use while charging).
This is my ten minute repair using what I had to hand . . . and it works.
Step 1: Tools.
Step 2: Materials.
Step 3: Assembly.
The iphone lays on this.
Batons are cut and these are the ends that hold the iphone and the charger plug together ( see 3rd photo).
Step 4: The End.
It's ugly but it works and the iphone can be used whilst charging.