I've got a TLR too
Done my plugs a few weeks back
Have you re-fitted the wiring plug for the horn ok?
I'm pressuming you took both side panels off to get access to rads to get to front plug etc
Have you checked the fuse/relays on right hand side and the big jumble of wires on the left by the rear of headlights?
Stating the obvious but how old is the battery in the alarm remote?
(some bike alarms wont respond if the kill switch is in the OFF position)
Have you got a spare remote and/or remote battery?
Just check and re-check all wiring plugs that you have to undo to get air box out etc
To be honest, I haven't done much checking. The only plugs that I unplugged were the indicators. I took both side off with the fairing. I've got two remotes. I checked the batteries in both and they are both ok (I think) with working batteries. The bike battery is a few years old, but I leave it on trickle charge when it's parked up - the lights work well so I don't think it's that.
It's weird...It was ok when I first change the plugs. But after trying to start it, the alarm went a bit odd. Firstly, I noticed that the immobiliser wouldn't switch off, then when I turned on the ignition, the alarm went off but I couldn't switch it off. Time to try and find some troubleshooting guides for a Meta 300.
I'll have a play over the next few days.