ONS has a bug, and the Pull parser is visibly faster.

There is a stupid issue in the ONS interface, wherein you get more than
you bargain for -- want an area containing a specific postcode, of
specific level type within a specific hierarchy? We'll throw in a
completely unrelated area from a different hierarchy FOR FREE!
The Pull parser cometh. Also, the method calls got fancier.

new FindAreas().forPostcode("...").ofLevelType(0).execute();
is better than
new
FindAreasMethodCall().addPostcode("...").addLevelTypeId(0).findAreas();
Sync from Filip-PC/1
Sync from Filip-PC/2