At first glance I'd say a minerally profile - I've tasted milds with minerally water and it's worked.

 

That was my thought. I would remove the roasted barley completely and use enough chocolate malt to get the color within the guidelines. The recipe looks darker and roastier than necessary. I could be way off though.

 

I'm not that knowledgable in water treatments even if I do try to adjust my water some, and just like Ozarks say, I keep my water profile balanced for a Dark Mild. You might prefer a roasted note in your Mild, personnaly I use no roasted malt, or chocolate, but keep the color up with extra dark crystal and invert sugar of darker kind.

 

Honestly I don't have much experience with the style but thought the chocolate would give you a bit less roast character than the RB. If you wanted to keep the RB you could just use less of it as well.

 

When i want to try a new beer and find a respectable author of a recipe, i usually stay pretty close to the recipe. That does sound like a lot of roast but there are other malts to blend with it and the ibu's are low so will lose some of its edge maybe? Then after brewing it, change it to personal taste if need be. As far as water, Palmer usually lists his water for his recipes.

 

Not a lot of advice, but I'm very keen to try some milds and this looks really interesting. Especially interested in the opinions on whether chocolate is really just 80% of a black malt/roasted barley as some people say or something more in the middle of a crystal and a black as most people seem to think. The times I've used chocolate it's a small part in a grain bill and don't really get a feel for that.

 

If/when I've used chocolate malt, I've preferred using low colour chocolate malt. To me it feels less roasty and bitter and with actually hints of chocolate, which I don't think ordinary chocolate malt has.

 

My preference of those two is EKG... I sometimes get weird flavours from fuggles that makes me hesitate to use it.

 

Either will do - matter of personal preference - and both are to style.

 

I used fuggles in my Christmas Ale, which is not a hop forward beer, but I can only hope that I can replicate this brew next season.

 

I brew mild ales quite often, but I'm not a fan of using roast malts to achieve the desired colour or taste... Traditional 20th century British commercial mild ales didn't use a lot roast malts, if any. Dark milds usually got most of the colour from brewers caramel colouring and various grades of invert sugar, with maybe a smattering of roast malt, and some crystal malt. Here is quite a typical mild ale recipe from the 1980s...

http://barclayperkins.blogspot.com/2012/05/lets-brew-wednesday-oldham-1987-mild.html

(The invert No.1 can be subbed by Golden Syrup)

Milds like this were still commonplace in pubs when I was a lad and can still be found on draught nowadays. Lovely they are too.

As for hops... Ordinary milds would have fuggles and posh best milds would have goldings.

Oh... before I forget. You may want to try this water thingy for your water profile. It has a target liquor for mild ale...
https://www.jimsbeerkit.co.uk/water.html

 

Tip... That recipe required 6 SRMs worth of brewers caramel for colour adjustment. Instead you could. use 2oz roast barley, ground to a powder and added to the boil kettle @ 10 minutes before the end of boil. This will impart the colour, without adding a lot of astringency i.e. maximum colour / minimum flavour. Or not bother with colour adjustment...

 

You could also just put that black malt on top of your grain bed before you sparge.... There's Sinamar - black malt extract - for color adjustment too.