Ive had the car a week and still getting to know it. So, in the process of adjusting the clutch i was under the L/H Front at the slave cylinder and i took the below pics. Looks like it has underseal already? Thoughts? Am i right in saying that area would be just paint?
I was planning on getting it treated underneath, but the initial few inquiries up in ABZ have drawn blanks.
I may therefore do it myself (de-scale, hydrate, prime, Lanoguard/BH UC)
NC I’m thinking, looks very much like it?
There is some undersealing done under there but it does start to come away especially at the seams/joints in the chassis over time. That cross brace will unbolt, I did mine, removed it and painted around the area and the brace and replaced.
Take particular note of the rear end of those chassis rails and around the rear sill wheel arch area, this is a common rust area, in fact priority area to treat.
That’s as it left the factory, standard Mazda hit n miss underseal.
Quite.
If you don’t decide to do it yourself give Barry Cooper Motors in Fordoun a call, he has undersealed a few 5’s including one of mine.
cheers - will give him a call. 
Hi, I have been doing my NC today. Low mileage, only dry use for the last 8 years. Under seal
Looked ok except for some cracking on the seams.
I decided to investigate, surface rust had penetrated up to a couple of centimetres under the under seal.
Well it’s removed now ready for treating, painting them a coat of lanoguard as I do not want thick under seal masking issues.
Fortunately everything is solid but these pictures are what I could see initially and what I found when setting to with the scraper
.
looks kinda similar to mine…there is hope!
I agree on the thick underseal…if water gets behind it 
did mine a couple of months ago after recommendation on here.
found some time to investigate a bit more…Now, i had a look at this area when i bought the car, but obviously couldnt poke with a screw driver!
seemed ok…then…
suppose i will need to get the welder out, although i am half tempted to treat it and leave it for a year or so!
Also took some boroscope type videos
First is off the inner/outer sills - apart from first couple of inches, seems ok.
https://drive.google.com/file/d/1DqZ6P7TlyHYVAjMp6XSX6O0tki7UoG99/view?usp=sharing
then another for the rear subframe which looks ok inside
https://drive.google.com/file/d/1HwpD7nAWMWpANwZA2q_9pLydlOBkx0pt/view?usp=sharing
As I said in my post above the rear wheel arches need attention/inspection, a common spot for the crud to accumulate.
I’ve pulled some pictures off a post I did about mine over 12 months ago, another to watch for are the rear chassis legs, where the exhaust back box hangs off.
Behind the plastic sill cover too.
