UKH

Coming up for the renewal of my accident insurance. I normally go for an annual insurance as I generally take at least a couple of summer trips in Europe and then usually away skiing for 3 weeks. 

Annual insurance will take me beyond March 2019  so wondered whether this is going to be an issue?

Problem why ? Brexit ?

I am sure your insurers will have thought of this before they offer a policy for that period.

Yes, they've thought about it and e.g. the airlines are putting wording in to cover themselves for what may (or may not) happen after March 2019, see e.g.

https://www.theguardian.com/business/2018/mar/14/uk-holiday-firms-urged-war...

Austrian Alpine Club £50 a year.