Just here to add to those saying DO get it. Check the details of the policy and what is covered carefully but really don't leave it to chance.
Our mortgage advisor sold us ours, 2 separate policies for me and DH, that's important too, and I didn't give it too much thought.
In the nearly 8 years since we got it we have each claimed (1 x successfully, 1 x being processed currently, but absolutely should be covered according to the terms of the cover). It is tens of thousands of pounds and while we would've far rather not needed to, it makes a huge difference no matter what protection through work sick pay etc you think you might be able to rely on.
My only regret with our fairly large mortgage is that we didn't arrange cover that would have paid that off. Now that would have been a game changer and is what I would highly recommend even if it's twice as much to pay per month now.
We were both young, fit and healthy when we took out our cover just to add, with absolutely no reason to think we had any serious health worries heading our way..... hope you make a choice you'll be glad of 10, 20 years down the line 