I've converted this in Beer Engine for you and it's come up with a problem immediately. The OG is only 1.052. I've re-set it to 1.058 and the quantities are correct for that figure.
The second issue is the Lager Malt you've used. Steeping Lager Malt, as it's a Primary Malt, probably doesn't extract anything fermentable. Using the BIAB technique, and Grmski is the one for this, it would.
Anyway, here's the conversion as an All Grain, conventional mash recipe.
The FG figure will depend on the yeast.
Wheat Malt. 3.5 EBC. 2450 grams.
Pale Malt (Maris Otter). 5 EBC. 2000 grams
Lager Malt. 2.5 EBC. 395 grams.
Crystal Malt, Dark. 300 EBC. 54 grams.
Chocolate Malt. 1050 EBC. 120 grams.
Carafa 3. 1200 EBC. 120 grams.
Willamette Whole. AA 4.7%. 60 mins. 45 grams
Cascade Whole. AA 5.7%. 15 mins. 20 grams
Spalt Whole. AA 4.5%. 5 mins. 25 grams
Spalt Whole. AA 4.5%. 5 mins. 25 grams (2 minutes plus 5 minutes steep)
Final Volume: 20 Litres
Original Gravity: 1.058
Final Gravity: 1.015
Alcohol Content: 5.6% ABV
Total Liquor: 30.1 Litres
Mash Liquor: 12.9 Litres
Mash Efficiency: 75 %
Bitterness: 31 EBU
Colour: 117 EBC
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