In this kind of situation whenever you're making a beer from a particular country, think what a brewer from that country would do. Which in general would not involve "foreign" ingredients, and for British beer in particular it's generally a terrible idea to try to adjust colour using "flavour" ingredients - if you don't have brewer's caramel or touch of black, then forget about trying to hit a colour target. And diluting the Otter is not going to help with maltiness...
[I wrote most of the following before the thread turned to these topics, but I didn't post it]
The main cause of "thinness" is kegging - it really doesn't suit British beers, certainly not in the <4.5% range that are normally served on cask in pubs. CO2 is the fifth ingredient in beer, and like everything else in British styles, it has to be in balance with the other ingredients. I recently had a keg mild from
Cloudburst (which for those who don't know is a bit of a hype brewery, got "best smallish brewery" at 2021 GABF etc - their IPAs are terrific) and you could tell there was a decent beer trying to get out, but it was completely swamped by the carbonation - felt like it was probably the end of a keg, it was more than just the usual over carbonation). So you need balanced carbonation - and the fine mousse of natural carbonation is part of the nature of these beers. Think of the flabby bubbles of Coke versus the mousse of nitro Guinness - Guinness overeggs the carbonation because it's part of its "thing", and nitro bubbles aren't quite the same, but for those who haven't had real cask then imagining nitro Guinness with about half the gas will give you a target to go for. At least for northern beer served through a sparkler, it's different in the south....
And don't be afraid of dryness, that's what keeps you coming back for the 5th and 6th pint, whereas sweetness sates you. It's one of those great myths in the US, that British beers are syrupy sweet, while that may be true of half-conditioned beers in Heathrow Wetherspoons, it's not the reality.
Yeasts like Windsor being available for sale don't help - but people forget that Windsor was never used on its own, it came from a multistrain that included a Nottingham-like strain to get the attenuation up - and that wasn't even in the North proper. Pre-racking gravities can be a bit misleading, but eg Ron Pattinson had a table of 1960s keg bitters that
averaged 80% apparent attenuation, and of course there's the famous example of
1970s Boddies that was over 91% and is mourned as a legendary example of bitter.
Oh no - different in almost every way, different water, different yeast, less crystal, everything. People don't realise how much regional variation there is in British beer, tourists tend to think everywhere is like the Thames Valley when it's if anything a bit of an outlier. Remember that Burton was obsessed with high attenuation, to minimise residual fermentables that might ferment in tropical weather en route to India and cause "barrel bombs" on a ship. Obviously pre-ageing in barrels infected with Brett etc was part of the story, but there's a lot of members of the saison family used in northern England, particularly in Yorkshire squares. You get a really distorted view of British yeast from the US yeast labs but you only have to look at the Brewlab catalogue to see that maybe 40-50% of their descriptions mention some kind of phenolic character, which probably means at least one saison-type yeast in there.
Certainly you can taste the phenols in eg Sam Smiths cask OBB, and in good pints of Harvey's Best - the Harvey's yeast originated at John Smith's and has had a saison-type yeast isolated from it.
Talking of Brewlab yeasts,
Malt Miller have *finally* started stocking their slopes, at £6.99 compared to £9 for White Labs/Wyeast - hopefully that should encourage a few more people to use them, but it is a question of use them or lose them!