Title Deeds not previously updated

When my mother-in-law passed away a number of years ago, her will stated that her share of the house should pass to my husband and his sister. The title deeds at Land Registry were never updated to reflect this change so her name remains on there. My father-in-law has now sadly passed away. They had mirror wills, so his share also now passes to them. Is the fact that the title deeds hadn’t been updated now going to cause an issue obtaining probate?

Karen - no. Probate doesn't look at the registered information. 
And there was no legal requirement to update the register following her death or transfer it to new registered owners for example. 
HMLR Guide: Start - External  · HM Land Registry

Thank you so much for your prompt response. That’s a huge relief.