The HW35E, and 35s in general were popular for Bell Target in the UK and target plinking in Europe. HWs in general were easy enough to buy in .177 if you wanted one.
Thing is to get that .177 going at a good velocity is harder than shoving the bigger .22 to get to the same power. Low powered target rifles aren't having to work too hard but hunting then its a big ask.

For 12ft/lbs then .177 is proven to be an advantage at distance as the FT boys show. Hunting its all about pellet placement perfection, so I hunt with a .177 unless in the farmyard where 20m is a long shot.
I part exchanged a Webley MK111 for a FWB Sport 124 in 1982, and my success rate went up. In ruth now I don't use an air riofle to hunt beyond 30m anyhow, as I have other rifles to do that.
In the old days a hit was good enough as the farm terrier would be onto anything in a flash. Few now have a terrier.