Drafted Will before divorce: Invalid?

pbartlett

one option would be to apply to the court to have the will declared valid - more likely to succeed if it was crystal clear what the deceased wanted...

xylophone

There are replacements named in this will who should be able to get probate.

The OP says

The Will does state that my mum should be primary executor and inheritor. It also lists a series of people who should act as executor and inherit should my mum die  (I am next to inherit after my mum). 
The only other thing I can think of is all the named executors (95+ and in a nursing home) have renounced or not legally capable of executing the Will (my mum).

Those named as executors are not (except in the case of the OP's mother) legatees.
The other named executors have renounced.

The will is not invalidated by divorce or renunciation but  as there are no other named exors  able or willing to apply see

https://www.co-oplegalservices.co.uk/media-centre/articles-jan-apr-2018/what-happens-to-my-will-after-divorce/

Once a Decree Absolute has been issued to end your marriage, the terms of your Will automatically change. Anything that you have left to your ex-spouse in your Will would be dealt with as if they had died on the date that your marriage legally ended. As a result, whatever they were set to inherit would then be passed on to the next beneficiary who is entitled to it, in line with the terms of the Will. If everything had been left to your spouse, with no other beneficiaries named, then your Estate would be dealt with as if you had died without a valid Will in place at all (known as dying “intestate”).

Who will act as executor?

If your Will named your ex-spouse as an Executor, but it also named other Executors, they will still be able to act. If your Will only named your ex as Executor, then an alternative Executor will be appointed by the Court. This will usually be a friend or family member.

https://www.thegazette.co.uk/wills-and-probate/content/103470

• A grant of letters of administration with will annexed is when a will is being proved but not by the executor named or if no executor has been named. For example, the grant could be taken out by a named beneficiary.

Mojisola

xylophone said:

There are replacements named in this will who should be able to get probate.

The Will does state that my mum should be primary executor and inheritor. It also lists a series of people who should act as executor and inherit should my mum die  (I am next to inherit after my mum). 
The only other thing I can think of is all the named executors (95+ and in a nursing home) have renounced or not legally capable of executing the Will (my mum).

The other named executors have renounced.

Thanks. I thought the OP had said that they were an alternate executor.

As going through the intestacy route results in the same result as the will, the OP should just get on with it.