I've found it to be a general characteristic of most English lasts across a variety of makers. The heels relative to the forefoot width tend to be significantly narrower than both AE and Alden, but particularly so, Alden.
Though there are exceptions with some English boot lasts made with broader heels, and a tendency at least for many Trickers' country lasts to be so made also.
The general shape and proportion of a last can often be better discerned from photos of the bottom of the soles.
This is the Alden Indy -
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This is a Cheaney Jackie III chukka on Cheaney's 125 last -
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This is Crockett and Jones' Islay boot -
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And a comparative difference, though to a lesser extent, can even be seen in some Portuguese made boots. (Portugal can be a good source for less costly quality footwear.) This is Herrings Portuguese made, Blake-stitched, Coleford model -
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In all four instances the ratio between heel and forefoot is significantly greater than Alden's Indy boot. I.e., the Alden Indy boot has broader heels. (And waist, also.)