Alejandro Melchor of Barcelona has sent me the following e-mail, bringing to my attention Pete Tamburro's recommendation of 9.Bg5 in the Fajarowicz variation after 1.d4 Nf6 2.c4 e5 3.dxe5 Ne4 4.a3 Nc6 5.Nf3 a5 6.Qc2 d5 7.exd6 Nxd6 8.Nc3 Nxc4. Tamburro's move is better than Harding's 9.Qe4+.
Some notes and analysis on Philidor Counter Gambit, Fajarowicz and Latvian Gambit in http://njscf.proboards2.com/index.cgi?board=amate blog of N.J. Chess Federation.
Remarkable a possible refutation ( Pete Tamburro ) on Fajarowicz with your idea 3.dxe5 Ne4 4.Nf3 Nc6 5.a3 a5!?
All the best!