House Mild (Not Mild!)

Today was my first attempt at creating a house mild. I wanted something that wasn't pale, but not stout like in colour. I was aiming for a 'post war' strength, that is sub 4%, nearer 3. My original recipe is in this post, but on the day I subbed out the pale for lager malt (as I had a bag open that I wanted to use up), and changed the sugars slightly as per below;

Lager Malt         2270g

Chocolate Malt 121g

Pale Crystal Malt 121g

Amber Malt         61g

Black Malt         61g

Demerara sugar       200g 

Golden Syrup          150g

The mash didn't go to plan at all. I had wanted to mash at 67°, batch sparge at 77°. I over heated the strike water, then let it cool to much, so the mash was at 65°. Additionally, something went wrong with the sparge and it kept sticking; once I fixed this, I only managed to get 18L after the boil. I suspect I didn't measure out the sparge water correctly. The end result was that the final gravity was 1040°, much higher than the 1033° I was aiming for. Obviously, this will result in a much stronger beer than planned. The sample looked good, and tasted very promising, so we will just have to see how we get on. I pitched Fermentis S04, which is a yeast I haven't used since my kit brewing days, with the FV sat in a water bath at 17.5° +/- 0.5°.