The benefits of disclosing mean you are then protected by the Equality Act 2010. This means that your employer has a legal obligation to consider reasonable adjustments to your work role. Reasonable adjustments can be anything from moving your desk location to make it easier to access the toilet, working from home one or two days a week, using outlook and email to remind you of deadlines and agreed work projects or putting in a stair rail.
There are useful guides written by the MS Society which explains about MS at work in greater detail:
and they have published one for your employer to read too: https://www.mssociety.org.uk/care-and-support/resources-and-publications/publications-search/ms-in-the-workplace-an-employers-guide#