Defender 110 td5 electrically dead

Hi guys , I have a problem with my 110, let me tell you the story, -
The 110 has always been reliable but the spigot bush started squeeling and the rust worm was devouring the rear chassis, so I decided to rear 1/4 the chassis and change the spigot bush, these jobs done and ready for lights test and engine start, not to be it seems, turn the key and nada, zilch, not a faint glow of life anywhere, no dash light, clicks or fuel pump whine.
Battery is good, earths removed and cleaned on chassis and g box, Ecu disconnected whilst work was done, now reconnected , all the obvious things done.
12.8 v to the starter but I don't know where to go from here?

Do the side lights and hazard flashers work?

Sorted, the wire from the fuse box under the drivers seat had been connected to the negative terminal, put a new battery on with the terminals the other way round and never thought about it.
Quick glance at the wireing diagram showed it up.