worn rear dropout and bad wheel alignment

So it appears that my non drive side rear dropout isn't flat. So depending on my chain length my wheel alignment goes from being ok to being a complete mess.

heres some images to illustrate whats going on:
Starting off pretty flat, happy days...

...Oh, that doesn't seem right.... that's a lot of light.

... still all over the place here...

... ok right at the back.

for good measure heres a snap of the drive side. all ok on this side:

I commute to work daily on the bike, currently running with the axle right near the front of the dropouts. All seems OK, but I would be much happier if i could have it seated further back. I'm unsure whether to:

a) leave it the hell alone, its working OK
b) maybe approach a frame builder to see if anything can be done to fix it. Does anybody have experience of anything like this? Maybe some material could be welded on and then machined until flat again?
c) put a big washer between the wheel nut and the outer surface of the dropout to span the recessed bit? This doesn't sound sensible, but maybe somebody has some experience either way.

finally heres an image of my bike for "context":

grateful of your thoughts. thanks. josh.

Such a sexy bike

I suspect some chain tensioners might solve this....

https://www.amazon.com/Origin8-Chain-Tension-Adjuster-Black/dp/B001GPJY1O

Looks like basic budget dropouts, possible overtighting of wheel nuts has deformed them slightly.
Slipping a big washer under the nut may do the job.
Running chaintugs on forward facing semi horizontal dropouts may be a faff getting set up.

@popdown you have to take credit for finding me such a nice frame!

@853superfly the dropouts intrigue me, as you have noticed they aren't forged. But the rest of the frame has fiddly fancy lugs. Seems odd! I guesstimate that the frame is from the 50's but have no evidence to support this. I bought the frame stripped of paint so know nothing about it. It has 531 stamped on the seat tube and a serial number on the bottom bracket shell, but that info has never helped me identify it.

The original headset cups had on OD of 30.7mm. Which apparently, according to sheldon brown, means its either Austrian or East German.

I agree tugs will likely be a pain, but will see how i get on.

Big washer would do the trick but finding a suitable one isn't always as easy as it sounds.

You need a good tolerance around the axle (more on this later), a fair bit of thickness so it doesn't just deform along with the frame and a large enough o.d. that it'll do the job you want it to do.

Instead of searching for a washer that fits the bill, I buy chaintugs like these,

And modify them slightly.

The silver threaded shaft is just screwed into the round bit that goes on the axle and held in with a bit of locktite. Lock 2 nuts together on the shaft and you can unscrew it. You're now left with a thick alloy washer that doesn't weigh a ton, is a snug fit on the axle and has a good o.d.

(There's usually about 5-10mm of thread in the round black bit so with the correct size bolt you can get the chain tug function, save yourself from having to carry around an 8 or 10mm spanner and you wont have loads of that shaft sticking out the back of your track ends)

I like that the 'washer' locates into the slot in the dropout (it doesn't serve much purpose but, you know...) and they are usually a nice tight tolerance fit on the axle so won't flap about on the axle and find their way down next to the locknuts inside the frame when you remove/refit your wheel.

First thought from the glimpse of the fancy lugged headtube was it might be an old Carlton.

Seatpost size can sometimes help indicate tubesets, although 531 stamped into the tube is good clue :)

http://www.hilarystone.com is worth looking at, you might see something similar and he does do a lot of links to various brands history.

Butchering chain tugs is proberly a good bet unless you have a magic pot in the shed full of assorted washers and axle spacers.

@M_V thanks for the detailed explanation. I went ahead and ordered some, will see how i get on! From the image it looks like i might have to reduce the thickness of rectangular lug that sits in the length of the dropout.

@853Superfly I went down a rabbit hole yesterday and spent many hours looking through all the builders here http://www.classiclightweights.co.uk/builders.html I haven't managed to find any lugs that look similar.

The frame takes a 26.2mm seatpost.

Heres some pictures from the seller before I had the frame powdercoated:

A chaintug should work, seems strange it's moving in the first place.
Are you using proper axle nuts with a "textured" underside?
I'd be tempted to try some different nuts with a larger diameter.
I don't think a washer would work as it'd be too slippy.

Mad-nice lug work. Never seen the like.

Didn't think this warranted it's own thread, but it feels kind of related to the OP (and my picture is definitely of equal quality...). I'm wondering if my chain tensioner could be made more effective if the bolts were flusher with the frame.

Or, put another way, is precise use of an angle grinder on my dropout a good idea?

I'm convinced my wheel goes out of alignment or the chain goes slack more often than they should, is this something people just put up with or is there a simple improvement I'm missing in this area? Cheers!

Bike: Charge Plug (v1)

Or perhaps I'll just replace the cracked bearing nut before digging out the angle grinder

What wheel/hub does that nut belong to?

They're "Charge" branded deep rim wheels. I've had them a while