The Bombardier - Hitachi HS2 submission is based on the existing Zefiro 300 for the Italian market aka Frecciarossa 1000, aka E.T.R. 400 or ETR 1000 that started off as joint venture between Bombardier and Ansaldo-Breda before Hitachi bought A-B. It also has to cope with similar classic compatible route issues - also recently chosen for Spanish HS stock.
en.wikipedia.org
The tender precluded articulated designs, fairly standard UIC non France spec - e.g. 25.0m centre cars and no articulation.
Not really a problems as Alstom's own bid is very unlikely to get in the top 2 on technical scoring, hence it would need a near suicidal burning of their remaining cash pile from the heavy electrical asset sales to GE* (very well timed) to make an overall competitive bid. Hence they only have one competitive bid.
*Passing the toxic bad luck of the ex-CE units to yet another owner ABB had lucky escape, it bankrupted Alstom once and was probably going to do it again till GE bought the falling knife.