Heather ale - extract recipe?

[Calistan]

Hi all! After some travelling around Europe I'm back home and ready to get back into brewing (hope to progress to all-grain by the end of the year). I'll be going to the homebrew store tomorrow so I thought I'd ask for some recipe advice before.

What I have in the cupboard already:

Brew at Home LME 1.5kg
Munton's Malt Extract Dark 1.5kg
Warrior Hop pellets 100g
Admiral Hop Pellets 100g

33L fermenting bucket and another 5L BB fermenter. I'll probably buy another fermenter tomorrow, a 10L most likely which I'll probably use for the heather recipe.
15L pot in which to boil.

I'm still very new to extracts. So, I really want to try something with heather, whether it's gruit or not, but I haven't found many extract recipes online. Has anyone tried the Guardian recipe below? Or recommend something better for me to try? I don't think I'll be able to find any yarrow for instance. And I think I'll limit my brew to something small like 5L or 10L to see how it turns out.

https://www.theguardian.com/lifeandstyle/wordofmouth/2011/aug/03/viking-heather-beer-recipe

Heather beer

125g heather tips (softer green parts of the plant, with the flowers if possible)
30g dry heather twigs (to provide tannin)
60g yarrow (the feathery leaves plus the flowers if possible)
30g dried hops
1.8kg honey (the nicer the better, but cheap honey will be absolutely fine)
1.3kg malt extract (Edme SFZ or similar – from a home-brew store)
500g crushed crystal malt (home-brew store)
1 tsp dried carragheen (Irish moss)
1 sachet of ale yeast
25 litres of water

Steep the crystal malt grains in 10 litres of water at 65C, cover and leave for 30 to 40 minutes. Strain the grains from the "wort", as the liquor is called, remembering to throw away the used grains and not the wort (a terrible novice mistake!). Add 5 litres of hot water to the wort and bring to the boil. Add the malt extract, yarrow, heather, twigs and hops and boil for one hour. Savour the truly wonderful aroma. After one hour add the carragheen and the honey and boil for another 30 minutes, then leave to rest for further 30 minutes.

Drape a large muslin cloth over a large sieve and strain your brew into a 25 litre plastic fermenting bin. Top up to 25 litres by pouring some cold water through the muslin and its aromatic contents. Cover and leave to cool to room temperature. Swish with a spoon or whisk to aerate the wort until there is a bit of a froth on the top. Allow to settle then add the yeast according to the instructions on the packet. Cover.

After 24 to 36 hours a cauliflower-like head will have form on the surface. Skim this off and allow the beer to continue fermenting until the specific gravity has dropped to 1010 (this is where the hydrometer comes in). Siphon into clean beer bottles or into a 25 litre plastic pressure barrel. Check every day or so to make sure the pressure has not reached explosive potential. The beer "conditions" (carries on fermenting) in the bottle, creating more alcohol, reducing the sugar and adding fizz. It is ready to drink after one to two weeks, though I couldn't wait that long and drank a, slightly sweet, pint eight hours after bottling.

For the bigger fermenting vessel I'm considering some sort of grapefruit IPA or a sour beer... so I'll inevitably be asking about one of those very soon whenever I've done more research.

Thanks in advance.