I own a pair of the original Lambdas. (They are on long term loan to a colleague, otherwise I would get them out and do a bit of testing. I really need to get them back.) When I first bought them I got the transformer energiser. I then bought the SRM-1 mk-2. It was a huge improvement.
The SRM-1 has more than a fleeting resemblance to the 007t. They both share basically the same input stage, and the 007t's tubes replace the output transistors in what is otherwise a nearly identical topology. It isn't a particularly advanced design. Back in the early 80's they were doing the best they could.
Transformers have all manner of difficult problems to manage. To make at a sane price and get the quality isn't trivial. Doable, but not trivial.
If you look at Kevin Gilmore's high end designs you get near perfect amplification, but the level of complexity is jaw dropping. He seems to have thrown the kitchen sink at the designs. Commercial realisations are not cheap. Then again the current Stax amplifiers are not either.