If you do not male new Wills everything in his Estate will go to you. This should not be a problem because you can still carry out in original wishes as the money is yours to do as you wish. Will making itself is not expensive just a few hundred pounds. I would contact AGEUK who have excellent service
Wills are invalidated by marriage. It also costs to change a name on a Power of Attorney, which I have looked into myself because one of my attorneys has reverted to her maiden name, and my solicitor says it will delay things if the time comes, and she then needs to dig out all her paperwork to prove who she was.
My partner and I have been together for 25 years, and took out powers of attorney about 5 years ago. They cost us a great deal of money due to us both having children. Now he is terminally ill and we would like to marry while we still have the time. Our wills and powers of attorney will not change, but would we have to pay a big bill again just because my name will be changing?