Hi Davie and congratulations on getting back into work and finding a compromise that works reasonably well for you.
There are a number of dry eye preparations that people on the forum use including Clinitas Soothe and Systane. Other people may have other suggestions. So it might be worth trying various ones to see which one suits you best.
On the work front, have you seen the leaflets about KC and work that you can download from the home page of this site?
www.keratoconus-group.org.uk/sitev3/publications.html They might help convince your boss that your difficulties are real.
All the best
Anne