There are repair sections available .... look here ... https://yrmit.co.uk/product/extended-bulkhead-repair-panels-per-pair-land-rover-defender-series-23/
That deffo needs repairing, you should idealy take the dash out and have a look in more depth at how far the rot extends.
Changing the bulkhead is not for the faint hearted

Your right, the photo isn't great.
Time to get the welder out.

The rust is always worse than you think.

If that is what you can see I would wager there will be more that is unseen hiding under the dash.

Looks the same as my one I did last year on Landy (theres some photos on here if u look). I cant speak higher of the LRM products. I actually went to their factory/business them to pick them up and spent 30 minutes just chatting away - really great people and superb products.

I agree with Miktdish - changing the bulkhead is a massive job and might not need doing. Take the dash off and binnacle etc and have a good look. Make sure you spray loads of rust inhibitor in there while you are at the repair.

A great bit of advice I got was to only repair the areas that needed it. LRM have everything that you need, and dont forget new bolts. I cant see the front vents but if they are ok then the rust might not be too bad under the dash. Same with the footwells. I sealed everything with Tiger Seal when I was finished.

Just accept that its going to be a pain in the arse and get the TiG welder out. You might enjoy it!

Stumpy