Welding and the ecu's Will they lose memory?

Hi guys I'm about to undertake welding to the front wheel arches ( inner) where the rot has taken hold under the plastic guard. I will need to remove the battery and fuse box/expansion tank etc to get at the rot as well. As the battery and ecu will be removed is there anything that's going to need reset by nanocom. Small patch to do on rear chassis as well. Oh and all the diff and transfer box oils are being done as well as a full engine service. Loving the disco experience so far but still very apprehensive of any big issues croping up.
Thanks in advance folks and maybe some photo's/how to's to follow if I remember to take my camera out.

It's not a bad idea to unplug your ecu's when welding anyway I've read a few threads where after welding poeple have had problems with the ecu and getting the car to start up again .

Bcu fail

The big ECU beside the battery will be unplugged and removed total. Any others I need/should do??

as said...the biggest risk is with the BCU, behind the glovebox

Thanks guys I'll get it unplugged as well then. Any issues with it needing reprogrammed though?? or just plug it all back together.

as long as you disconnect the battery first no need of any reprogramming

Excellent many thanks.

off course at the end after everything is plugged back connect the battery as last

I might have been lucky, but all that was done to mine whilst fettling the rear nearside chassis was disconnecting the battery for 4 days. Fired up and checked out A-OK.