How’re your electrical skills @osprey68? It may be worth checking the charging voltage to discount any issues. You should be getting 13.5V min to about 14.5V (with revs) at the battery with the engine running, and 12.5 to 12.8V with the ignition off on a fully charged battery. EML should hopefully go out after 3 heat cycles.
you may find the engine light goes off after 4 or 5 restarts. you may also have to re enable the quick shifter in the settings and rider mode may have gone back to road mode.
A friend of mine had a similar problem with his Speed Triple - the battery seemed OK and if we connected it directly to the starter motor it turned the engine. But when we connected it as usual - to all the usual electrics - it seemed OK until we pressed the starter button when we heard the solenoid click but it failed to turn the engine. We tested the solenoid and that was OK. We tested the starter button and that was OK. To cut a long story short, these modern bikes are too smart for their own good - the 'brain' was detecting a good voltage when the battery was under no load. Then, when the starter button was pressed and the solenoid energised, the 'brain' detected that the battery was a bit under-powered under the high load and so it de-energised the solenoid. If it had just done as it was bloody told the bike would have started fine but it cleverly decided to over-rule the human, de-energise the solenoid and not even indicate what it had done. The solution was a new battery and everything was fine. The old battery was just slightly under-spec (CCA).
At the end of the day, your best bet is to just take it back to the dealer. They shouldn't charge you for anything unless it wasn't a triumph dealer you bought the bike from. I know original owners warranty is 2 years unlimited miles but if that follows the bike I'd just drop it off and let them do their thing.
Just wondering if this got sorted and what the issue was. Mine seems to die if left for more than 4 or 5 days... only bought it recently and I'm worried it will be costly