Oh ok. That's fair enough. My bike is a September 2016 build so I'm assuming it has the latest ECU because I've never had any issue with surging at all. Only issue I ever had was an abrupt on/off throttle transition which I sorted by adjusting the primary TPS.@suzukiguy. For some weird reason in the USA Suzuki named the 2015 model a "2016" one. So Dynojet are talking about the same bike.
Just downloaded the USA -001 map and it is still the same as the one I got in 2015.
The thing is the UK -501 map came out after Suzuki modified the ECU to cure the "surging problem".
I still have the original ECU that the -001 map was created on so maybe that's why it works for me. It's a shame Dynojet didn't give a reason for removing the -001.
So I'm guessing if I have the latest ECU I would be better off running the UK map?