My Turn Indicators Blowing 15amp fuse

there is a relay not a fuse for them look under the hood in the fuse block make sure you are getting power to them they both work on the same relay could be a bad ground

Vauxhall indicator problems on one side is always the big yellow relay under the black cover on pass side under bonnet. If none working now check its fitted properly, fuse not blown and not a defective relay. One relay works hazards and both sides of indicators. So are hazards working?

RT/SIG fuse #11 15amp - I/P fuse box . Fuse Block - I/P
In the center of the instrument panel, beneath the right side of the radio, in back of the right side console access panel.
This fuse is power to the BCM , When you put on the right turn signal , this is a voltage signal to the BCM . With logic ( programming ) the BCM then controls the turn signal !
Turn Signal/Hazard Lamps
The body control module (BCM) is responsible for controlling the turn signals and hazard lamps. When the turn signal switch is placed in either the left turn or right turn position, the BCM receives a signal from the turn signal switch. The BCM then sends an on-off voltage signal to either the left or right turn signals and their instrument panel cluster (IPC) indicator. When the hazard switch is pressed, the BCM receives a signal from the hazard switch. The BCM then will send an on-off voltage signal to all the turn signal lamps. All the turn signal lamps will flash including both IPC turn signal indicators.
There could be a DTC- diagnostic trouble code stored in the BCM pointing to the problem ! I suggest you take your vehicle to the dealer or a ASE certified repair shop that has the diagnostic tools to find the problem . Just so you don't waste your money replacing parts that don't fix it.
There could

Possibly turn signal relays do you hear the clicking when you have the blinker selector lever on?

The fuel pump relay is located below the right side of the dash to the left of the engine control module. There is also a 15amp fuse
for the fuel pump. In the fuse block under the left side of the dash
fuse #19. Hope this helps.

Sounds like you have installed LED turn signals in place of the original incandescent ones.

You will need to install resistors in line with each LED turn signal to slow the flashing down back to normal.
"Trackside" products makes a load equalizing resistor for use with LED turn signals.

Fuses are a SAFETY device. Never replace fuses with larger amp ones. Take the bike to an authorized repair shop and get it done right. There could be a short or relay problem that can lead to more extensive problems down the road. Safety devices are put in place to protect you and the system. Like in a home: if you run 14-2w/grd to light fixture the max fuse to use is 15amp fuse. never put a 20 in because the wire can melt at higher amps. Same with your bike. the wire is not rated to handel more than is was designed and fused for.

It sure sounds like a short in the left signal circuit. I can't say where the wires are routed but you may have one with failed insulation or pinched under some hardware.
You could avoid repeated fuse replacement if you buy a cheap digital multimeter from Radio Shack (if you are in the US) or alternately, from an auto parts store. One adequate for this would be under $20 US. Some have a continuity checker that sounds a 'chime' that stops when the resistance level rises a bit. Since the meter could be damaged if the short clears, it would be smart to disconnect the negative side (ground) of the battery. Putting the probes across the fuse contact will simulate the fuse for this checking but it will not let your signals function. I would punch the probes into the fuse holder, put on the left turn signal and start removing bulbs and checking the routing of the wiring. When the chime stops, you have found the culprit.