10a Ignition Fuse And 15a Instruments And Alarm Fuse Blowing

2018 Triumph Street Twin - no start and no display
Background:
Purchased 2 months ago, and the bike previous has only done 300 miles in the previous 4 years and was not serviced during this time.
I had immediately done an oil, coolant and filter change, and the bike has been running well since. The bike is parked outside on my drive so exposed to rain and sun, but it's riden regularly 3 days a week.

Issue:
Last week, no start and no light on instrument cluster.

Realized that 10A ignition fuse had blown, and the story begins.

Ingintion switch resistance test
| Ignition Switch Status | Resistance | Battery | 10A IGN Fuse |
|---------------------------|----------------|---------------|----------------|
| Key OFF position | 100 - 190 Ohm | Disconnected | Disconnected |
| Key ON position | 5 - 15 Ohm | Disconnected | Disconnected |
| Ignition switch unplugged | 90 Ohm | Disconnected | Disconnected |


Ignition switch fuse test
| Ignition Switch Status | Battery | 10A IGN Fuse |
|---------------------------|-----------|---------------|
| Key OFF position | Connected | Good |
| Key ON position | Connected | Blown |
| Ignition switch unplugged | Connected | Good |


I have removed all the relays, i.e. cooling fan relay, headlight main relay, EMS relay, starter circuit relay, headlight DIP/DRL relay and the 10A IGN fuse still blows.

On the triump street twin, there is a separate starter circuit relay and the starter motor relay, and when I unplugged the starter motor relay, eureka, the 10A IGN fuse didn't blow.
But that's when I realized that the 15A (Instruments and alarms) fuse had blown. And I suspect this was blown from the start. After replacing the fuse, and plugging the starter motor relay, the fuse blew immediately even with the key off the ignition.

Starter motor relay resistance tests removed
| Resistance tests | Resistance |
|----------------------------------------------------------------------------------|-------------|
| Resistance between threaded terminal (+ve battery) and Pin 1 or Pin 2 | 0.5 Ohms |
| Resistance between Pin 1 and Pin 2 | 0.5 Ohms |


Starter motor relay replaced
Suspecting that there was a short in the starter motor relay, I bought an non Triumph replacement, and the resistance behavior and the symptoms are exactly the same.

Starter motor connection from relay unplugged
I unplugged the starter motor connection from the starter motor relay, and the the 15A (Instruments and alarms) keeps blowing immediately.

In summary:
15A (Instruments and alarm) fuse blows immediately.
10A Ignition fuse blows when ignition switch is turned to ON.


Please do suggest on what should be the next tests which I should do to narrow down the problem.