Opening Trap

THE annual Jersey congress in the Channel Islands began today, with me seeded 19th out of 24 entrants in the Open.
Spanton (1914) - Jack Rudd (IM2253)
Botvinnik English
1.c4 Nf6 2.Nc3 c5 3.g3 g6 4.Bg2 Bg7 5.d3 0-0 6.e4 Nc6 7.Nge2 d6 8.0-0 Rb8 9.h3
Preparing Be3.
9...a6 10.Be3
More popular are 10.a4 and 10.f4, but the text has a respectable history.
10...b5

How should White proceed?

*****
*****
*****
*****
*****
11.Qd2?
This natural-looking move is White's commonest choice in ChessBase's 2019 Mega database, but it loses a pawn by force.
11...bxc4
Many players, including one rated 2505, have seemingly missed the strength of this.
12.dxc4 Ne5 13.b3 Bxh3!
Despite having lost a pawn, I manged to make a game of it, but lost in 49 moves.
Going back to the diagram, the analysis engine Stockfish10 reckons 11.f4 is equal, while Komodo9 has Black slightly better after 11.f4 or 11.b3.