I'm looking for some advice. Anyone done a Triathlon build?

After searching through lots of open mould frame retailers for a triathlon frame i think i have found a good one. TT912 in T1000 carbon. (i don't trust the chain stays on the TT915) So originally Tan Tan but i can see it on sale quite a few rebrands.

I'm trying to order to the UK. I'm not sure which retailer will be best or which store to use. Winow, Mira, Falco, Haideli or Seraph.

I'm surprised i don't see any TT/triathlon builds on here. Any other advice on frames?
The Rinasclta / Airwolf TT YFT058 geometry looks limited for me (im halfway between medium and large)
The ICAN TT012 TT016 frames have a lot of stack similar to road bikes which is a bit strange. Almost like they quickly redesigned a road frame. I think this is the same with the Winspace TT1550 frame. A few brands are still pushing Vbrakes.
Velobuild VB-TT-023 seem to have a good frame. Looks like they accept orders direct from their website but i think i prefer AliX.

I'm in a similar situation, looking for an aggressive geometry. I"m UK based.
I'm looking for a stack reach ratio near 1.37 on a large frame.

Speeder SC-R49D would have been perfect but the 10MOQ :/
Seraph X36 is probably my second choice but geometry looks closer to a TT bike with stack:reach at 1.33
Yishun R086D pretty good at 1.38

These brands don't seem aggressive enough
Seka
Velobuild
Haideli
Elves
Tantan

Just thought i would add my research. Maybe it will help.