Sounds nice. If ever we missed the photos!

How about light blue ocbd with those dark jeans? Or navy blue or dark green polo and chinos?

I know you’re adverse to the high street, but those shops are filling up with off white jeans right now. Straight seems to be taking over from skinny thank goodness. Spotted off white 501s aplenty on my Friday jaunt today.

A broadcloth shirt.  Agreed.  Plain.  Agreed. 
I've long been a sucker for Madras shirts but this is only the second I've ever owned.  The first was a good deal more vivid and made of a thicker cotton.  I remember wearing it with a plain white OCBD, jeans (probably L.L.Bean) and loafers.  This would be around 2008. 
Madras shirt wise, I always liked that idea of Chris_Hs, wearing one in the autumn and winter beneath a jumper.  I think Chris meant a crew neck, though, with just a touch of colour showing.
Off-white jeans?  Sounds interesting but am I too advanced in years to pull it off?  I wonder.

A navy blue poloworks under a madras jacket I find, providing that fits with the jacket colours of course which it normally does.

I picked up a lovely late 60s green and white Madras jacket a while back which needs the sleeves taken out so gone unworn last summer...but it is a sort of autumnal set of colours which makes it more possible to wear casually. I look forward to the chance to try it out. Could perhaps get away with navy polo and raw denim, or perhaps chinos.

It's a bit of a weird find actually, and it had major surgery at the back where it had been torn (looks like it may have always been like that) and also surprisingly padded shoulders (yet don't look it when worn, if that makes sense).

A certain amount of padding is regarded as desirable by some, I think.  Is it not a myth that the 'natural shoulder' has none whatever?  The trick, I guess, lies in the tailoring: knowing how to get the effect just right.  But I know next to nothing about tailoring so must yield the floor.
Nice to know, however, that these jackets (or 'blazers' as some insist on calling them) are still finding favour, even here in stuffy old England.

^ How to avoid parody.  Absolutely right.

Contemporary not so much.

Which always reminds me of:

https://www.thedailymash.co.uk/news/society/middle-aged-man-was-wearing-non-superdry-clothing-2014040785462

But is Ivy retro? True, the best of it was made years ago and clearly takes a lot of knowledge, effort and luck to track down. But a lot of the gear, especially at the casual end, is pretty widely available. Only in the last few days there’s been talk of John Lewis, Community Clothing, Uniqlo.
Anyone could go into any department store and come out with Levis, a Ralph bd, a merino top and a pair of boat shoes. All on their own fairly classic, some would say hum drum items. I don’t know if putting it all together makes it retro? I mean in the same sense as mods, teds, ‘The Chap’ tweed style?

I do think rarity value is a good thing. But I’ve done my time as part of a scene where rarity and particular brands were too highly prized. I’m kind of done with that personally.

I still can’t help putting my clothes in some sort of pecking order - Brooks is better than Gant is better than Tommy - but the sensible side of my brain knows that it’s not true to any great extent. Other then if I trash the Brooks it’s less easy to replace.

I’d wear Timberland boat shoes. If I needed some and they looked right at the right price. But I only have myself to please. It’s phenomenally unlikely that I’d ever be considered some kind of Ivy Ace Face but I’m happy with that. It’s just the look, the vibe I’m going for these days.

This is where Ivy becomes confusing and contradictory.  The goalposts get shifted around, interesting games are played. 
Refer back to Elms and his notion of clothing as an 'interface' between the wearer and those observing the wearer.  It's all social and psychological. 
The football 'casuals' were onto something here with their adoption of 'straight' clothing such as Lyle and Scott sweaters.