I don't have any heated gear ( I have enough built in "insulation"
gathered over many years of personal abuse

), however :
Pages 80 & 81 of the ( UK ) Owners manual gives details of the electrical Accessory Sockets :
• All models have a socket fitted to the left
hand side of the engine, below the
rider’s seat, and a socket fitted in the
stowage box.
• Trophy SE models have a pillion socket
fitted on the left hand side of the
motorcycle, below the luggage rack. This
socket is available as an accessory kit for
Trophy models from your authorised
Triumph dealer.
• Models fitted with a Triumph top box
have a socket located inside the top box.
The sockets will provide a 12 Volt electrical
supply. All sockets are protected by 10 Amp
fuses, therefore items with a current draw
greater than 10 Amps (120 Watts) must not
be plugged into the socket.
You won't be able to access the Glove box or Top Box sockets ( without modification ),
for plugging heated clothing in, but using the rider and pillion ( if fitted ) sockets,
it looks like you should be able to draw up to 10 amps of current from each,
so provided your heated clothing has a Power rating below 120 watts total -
for everything connected into ONE of the sockets, there shouldn't be a problem

Looking at some Spec's for Gebring gear on "Revzilla" you can expect a heated Jacket to draw around 6.4 amps,
Pants around 4.4 amps, and Gloves around 2.2 amps, so you could wear jacket and gloves,
but not jacket, pants and gloves which would blow the fuse ( at those ratings ),
so it's important to check the rating of the gear you are buying / have bought, before plugging it in !
