I had to check on this, because I have grown E. pininana and wildpretii which are the big brothers of webii with limited success, and as I suspected webii is also a biennial sometimes stretching to triennial in the cooler weather of the UK. In fact the couple of times I managed to nurse Echium through to flowering it required three years and a couple of mild winters in between. You may have been luckier where you are but in simple terms I think it is almost certain that it should not have been cut back, it grows more each year on the previous growth. It is considerably smaller than the the 3 super sized ones (towers of, jewels, flame and snow) so I think if your pot was big enough you might have managed it. Some plants recover after severe cutting back but in this case I would doubt it but you could hang on and see. Although it grows like a weed on the island of La Palma, if it's like it's big brothers then it is just possible to grow here but is difficult because of our weather. Sorry if this is a bit vague but hope it helps a bit.

I'd be surprised if it has survived the winter, doesn't like the cold at all. Agree it shouldn't have been cut back.