In reply to Sharp:
Sorry to hear of your loss.
I was able to adminster my late Mum's estate - even though her will was declared invalid , and I had to go through Probate - which slowed things up like getting access to funds from bank accounts and insurance policies. The total value of her estate (including proceeds from the sale of her house) fell well below the level of death duties, so was relatively simple to wind up -- although the house did take 12 months to sell.
Mum's will - though not strictly legal ( it had not been correctly witnessed) so she was deemed to have dies 'intestate'.
Mum had made specific bequests to ther family members in the invalid will, and my sister and I as main beneficiaries and were in full agreement that mums wishes were honoured in due course.
Once probate had been granted, everything fell in to place.
As your gran had obviously left a legal will, you will be able to get the necessary documents allowing you to wind up matters very simply - without tne need to involve a solicitor - though you will have to expect to spend a fair bit of time in correspondence and on the phone.
The Probate service has some very helpful information on its website.