The benefit of having more cars in the household than driving licence holders is that repairs can be undertaken at leisure. Following the MOT fail, there was quite a bit of work to do on the Daihatsu.

Pics of the problem areas:

I'm set to, trying and undo the filler neck, I understand that this is actually subject to an active recall in the UK as they rust and leak so will contact Toyota and see if they'll honour it - Toyota are the parent company of Daihatsu (who pulled out of the UK market in 2013) so we'll see. If not, and I b0rk the neck removing it, I'll order a new one from Amayama for £52 as this is not in its first flush of youth. 

The frontmost bit of grot will be fiddly due to the brake pipe bracket. not insurmountable, but fiddly. 

A few days later, the filler neck was now out and access was significantly improved for the rearmost bit of chassis rail at least The filler neck is held onto the car at several points, there are 2 torx head bolts going into captive* nuts inside the filler flap - these bolt through the inner wing into captive nuts in the flange at the top of the filler neck. On applying torque one of the captive nuts on the flanged bit of the filler neck snapped clean off, meaning it just rotated in the hole. The other began to undo a few turns, then stripped the torx head so the bit just spun in a mangled crater. Well, we're off to the usual flying start then aren't we?

On to stage 2, drill them out. If the metal the screws are made from is that flimsy then they won't put up much of a struggle, and they didn't

I was able to drill the heads off with my little drill and an 8.5mm cobalt drill bit

freeing up the top end of the filler neck from the inner wing. I used a magnet-onna-stick to clean all the swarf up.

Next up was the underneath bit. The neck is held on with 1x 12mm bolt into the bodywork, roughly halfway up the inner wheelarch, this came out without too much fuss and I copper greased it and bolted it back in loosely (note to self, its not lost, its in the original hole), then there are 2x rubber joiners between the bottom of the filler neck and the inlet of the fuel tank. These are attached with adjustable screw type hose clamps which were TFFM,BT. One survived my attempts to loosen them off, but the other one - the main filler neck one - snapped. The threads of the screw section were solid rust and almost impossible to get at to clean up with a wire brush, so RIP clip thing. I'll replace with a jubilee clip in due course. With these off, I could pull the filler neck out of the rubber hoses after much wiggling and prising with a screwdriver they were free

You can see one of the spring clips on the breather hose on the left. I stuffed the main filler hose up with an oily rag to stop all the petrol fumes coming out and from moisture getting in, and used my engineering prowess* to wrap a foam ear plug in electrical tape and stuff it into the end of the breather hose

Then with some wiggling, the neck came out

Its seen better days TBH. Its not holed (yet) but is pretty grotty and rusty, and the section that bolts to the filler flap end is megab0rked now so this will be getting replaced I think. I'll keep it in case I can get it done under the recall, but I'm doubtful - I imagine I'd need to present the car for the dealers to do the job, rather than them just give me the part but we'll see. 

With this done, access to the rearmost bit of chassis rail is much better

With the damper undone from the top mounting and the spring pulled out, access to the grotty bit (to the right of the spring) should be pretty easy. I need to have a think about the brake pipe bit though.