MES / ECU connection drop out problem

[Jimmystratos]

Can anybody help me?
I'm using the free version of MES to decide if I want to buy the licenced version for my Motronic 1.7 ECU from an Alfa 164 24v. This requires the VAG KKL interface with the Fiat 3-pin adapter.
I'm using a new USB KKL Interface Stardiag K609 from electronic-fuchs and an up-to-date laptop on Windows 10.
I've navigated the driver / latency minefield and MES talks to the ECU happily. However, after 5 - 10 seconds of data it cuts out and connection needs to be re-established and parameters / graph reset. Is this a feature of the free version that improves with the licenced version? I really need the data to be over a few minutes to get what I need.
Any advice gratefully accepted - swearing doesn't work, I've tried!