The Suzuki outboard forum is, regrettably, not actually run by or supported by Suzuki themselves. Its a forum set up and run by boats.net, probably as a way to get leads for their parts sales.
Kev - I posed the question about AGM batteries over on the THT forum.
Here is the link. The response from a major Suzuki dealer is instructive:
https://www.thehulltruth.com/outboar...-starting.html
Again, the finger is pointed at the installation as being the likely problem, and the common electrical install issues are identified in the response.