There is an ex government constitution lawyer who believes today's ruling is weak and could be overturned. He had promised to explain his reasoning tomorrow.Which they'll lose, as today's ruling was both common sense and unequivocal
There is also a QC who believes the government might change the terms of A50 to bypass this problem and therfore win the appeal by agreeing that A50 is reversible.
I don't think this is quite as cut and dried as you think. Otherwise the government would not appeal.