Goat whey and buckwheat loaf

Perfectly tasty but struggling to get any height. Not sure if that's because of the buckwheat or whey.

The dough was also very loose for a 65% hydration. Perhaps the buckwheat doesn't take much water like the T65?

60.0%	Shipton Mill white organic bread flour	300
40.0%	Doves Farm wholemeal buckwheat flour	200
100.0%	Total flour	500
32.5%	Goat whey	162.5
32.5%	Evian mineral water	162.5
4.0%	Fresh yeast	20
2.0%	Billington's Organic Golden Granulated	10
2.0%	Pro Fusion Himalayan Rose Pink	10
10	Hour autolyse with 60% of the flour and all the water
	Combine remaining flour, yeast, sugar and salt
1	Hour lazy baker knead
1	Hour prove and dust in a tin
21	Minutes at 225°C (start oven at max and turn down as bread goes in)