yes given that my employer a FTSE 100 publisher must have spent a huge amount time and money on this stupid law - can we claim this back against our tax bill.
Well, yes. Generally and imprecisely speaking, expenses are deducted from revenues and the net is what's taxable. Your employer will end up paying a little less corporation tax because of it. Whether it's a net loss for the government is another matter, as what isn't paid in corporation tax might be paid in national insurance and individual income taxes.
Could your employer sue the government for their compliance costs? Almost certainly not.
Could your employer sue the government for their compliance costs? Almost certainly not.