Young's sugars in 1975

There are rather a lot of different sugars. Though not all in one beer. Everything except Export Pale Ale includes malt extract. Presumably for extra diastatic power.

In addition to malt extract, the Pale Ales also contain No. 3 invert sugar and tiny amounts of caramel. The latter, presumably, for colour correction.

In the dark beers, it’s Flo Sweet, DAS and CDM. Not sure what the first two are, but the last is Caramelised Dextro-Maltose, a less readily fermentable sugar which added body and colour.

Total sugar content is around 6.5% for the Pale Ales and 14% for the dark beers. 

Young's sugars in 1975
Beer	Style	malt extract	no. 3 sugar	Flo Sweet	DAS	CDM	caramel	total sugar
BMA	Mild	3.16%		4.74%	4.74%	2.03%		14.67%
PAB	Pale Ale	2.15%	4.30%				0.11%	6.55%
YPV	Pale Ale	2.17%	4.34%				0.10%	6.62%
PA	Pale Ale	2.15%	4.30%				0.03%	6.48%
SPA	Pale Ale	2.22%	4.44%				0.06%	6.73%
SPA	Pale Ale	2.15%	4.30%				0.06%	6.51%
Ram Rod	Pale Ale	2.17%	4.35%				0.06%	6.58%
EXPA	Pale Ale		4.44%				0.11%	4.55%
Winter Warmer	Strong Ale	2.85%		5.71%	1.90%	1.07%		11.53%
Old Nick	Barley Wine	3.06%		5.10%	5.10%	1.02%		14.29%
Saxon	Lager	4.80%						4.80%
Source:
Young's brewing record held at Battersea Library, document number YO/RE/1/44.