To test this myself, I decided to brew a version of my golden ale to the same recipe as I've used previously, but using Maris Otter instead of Gladfield Ale malt.
Here's the recipe:
4.5kg Maris Otter
100g Gladfield Gladiator
10g Gladfield Dark Chocolate
10g Gladfield Roasted
5g Pacifica at 10 minutes
5g Riwaka at 10 minutes
5g Pacifica at flameout
5g Riwaka at flameout
1 pkt Mangrove Jack's Burton Union
1 tsp of Irish Moss
1 tsp of calcium sulphate
1 tbs of 5.2 Stabilizer
The calcium sulphate was mixed into the malt before mash in, and the 5.2 Stabilizer just after mash in. The Irish Moss was added with the 10 minute hop addition.
Single infusion mash at 68 degrees Celsius (154F) for 60 minutes. Mash out at 75C (167F), and boil for 90 minutes.
The target original gravity is 1.057, which I hit pretty well bang on on brew day, which was the Saturday before last.
Incidentally, this was also the first brew I did using the Grainfather upgrade kit, with improved connections and filters. Quite a big improvement.
*You might say that he was just somebody that I brews to know. But probably only if you'd had your sense of humour surgically removed and replaced with a poorly coded dad-joke generator.