Hi Andy,
Welcome to the forum. I "lurked" for several years here too before raising my ugly head and becoming a member. (I've just noticed in my profile that I've been here on the forum for 3 years come Tuesday. Seems longer). It's good to have you on board here.
"I have finally ordered my L1 Model 2 with B2 sub and T1"
Congratulations! If you've not already played through on before, make sure you fasten your seatbelt. I would expect you to have a feeling of being "blown away" by the system. Not because of the overpowering volume because it isn't deafening. More because of the way the sound is all around you and makes you feel a part of it, which of course you are. Any people in your audiences who've never heard an L1 live will should be more than impressed (some even "gobsmacked") by the sound.
"My question is whether there is a specific pre-set on the T1 to for a LR Baggs Anthem SL pickup?"
The simple answer to this is, unfortunately "No there isn't". But this does not by any means whatsoever that you can't get a really good sound out of the Anthem through the system. I've been using the Anthem since the first year it came out. I was one of the first (if not the first) users here in Germany. I've never regretted buying it and am always complimented on my acoustic guitar sound when using it.
"Or if not, can anybody point the way to an alternative pre-set that would work well?"
I tend to use the "Steel String with Cond" preset and use the zEQ to make it sound the way I want it to. This is what I've done for my own for my own solo program as I don't have any conflicts with other instruments. Don't be afraid to to try out anything and everything regarding Presets. There's no right or wrong here. If you find something you quite like but it's not exactly what you're looking for then you can "tweak" it using the zEQ. If the preset is for any type of acoustic guitar (which it probably will be) then the zEQ will react in this frequency area.
You may also want to try out the Flat, A Guitar zEQ preset. Here's a couple of screenshots:


What you may find helpful (and this is a suggestion I often make as I do it myself) is to record your trials with an audio recorder (if you have one) saying what preset you're trying (for future reference) and have a listen to it. It can sometimes be a great help. It can also help when setting up at a location. Place the audio recorder somewhere in the room. You can either listen to it through headphones or through the L1 (that way you can hear yourself how it really sounds in the room). This can help to get the volume levels of the different instruments/vocals right. Once you've got the mix right, you can control the overall volume with the master volume control.
When you've got settings you really like, you can save them as a scene.
There's a video of how to do this. Here's a link.
https://www.bosepro.community/...ine-scenes#lastReply
Just click on it and you should land there in a new window.
In case you're interested, there are also other T1 tutorial videos which may help you get started. If you follow this link it should take you to the right place. She videos may help you to shrug off any apprehensions you may have when first using a digital mixer (the T1 belongs in this category).
Just one quick mention regarding this "I will also be using this system with a TC Helicon Play Acoustic set up - keen to hear of anybody's experience in this area!" Don't use effects EQ's from the Play Acoustic and the T1 simultaneously (i.e. EQ from one or the other, reverb etc from one or the other. Doing both at the same time can lead to feedback susceptibility and/or mushy/unclear sound. There are several threads which actually do cover this topic. At the moment I've no more time and must dash.
I'll leave it at that for now Andy. I've given you a couple of things to chew on which I hope van help you in some way. As I've already said, don't be afraid to try out different presets. Whatever sounds good to you probably is good (no matter what the name of the preset is).
Tony