I have done this recently, and here are some notes I made about the process, which you might find useful. I've included some dates to show how it worked out for us. Hope this is helpful!
Background - my mother died in April 2022 in England, with a very straightforward will and estate. She was divorced, and had a house and some savings which took her a little over the inheritance tax boundary. She had 3 executors, who were also the beneficiaries.
Step 1a - Value assets. Draw up list of all assets and any debts. Inform banks etc of death. Accounts will be frozen. Ask each bank for "date of death" balance and inform them of change of address for post. Get estate agents to value property.
Step 1b - Apply for the IHT Reference number (you need this on your IHT forms, so need to send off for it at least 3 weeks before sending off IHT form) - use Schedule IHT422.
Sent off 28/4/22; received 20/5/22 [3 weeks]
Step 2 - Fill in Inheritance tax forms and pay IHT - IHT 400 and associated Schedules. These are paper forms (as of July 2022). You need to fill in about half of IHT400, then the additional Schedules, then the rest of IHT400. Once IHT400 is complete you will also need to fill in IHT421 (the Summary form) and I also had to do IHT435 (the Residence Nil Rate Band claim form). You will also need various attachments (eg estate agent valuations of property, copy of the will, etc, and I sent a covering letter detailing what I enclosed). There is a helpline (0300 123 1072) which generally was excellent (although on one occasion their advice was incorrect).
Sent off 10/6/22. I then received IHT301 and IHT302 on 18/6/22
[1 week - this is exceptionally fast, I think we were lucky]. These told me what IHT I had to pay (I opted to pay in instalments, because we had to sell the house first.)I paid IHT online on 18/6/22. IHT421 (the stamped Summary form) was sent by IHT to the Probate office.
Step 3 - Apply for Grant of Probate. This can be done online (and note that the online form asks slightly different questions compared to the paper one). The Probate office says you should only apply 20 working days after having sent your IHT forms to HMRC. After you submit it you are told what you need to send them by post (the original will etc) and given a Probate Reference number. And you have to pay for it (£280).
The Probate people have a "target" of dealing with cases within 8 weeks and you cannot follow up with the Probate Office until at least 8 weeks from the time of application. There is a helpline Probate info line: 0300303 0648 and a webchat facility (www.apply-for-probate.service.gov.uk/avaya-webchat). I used the webchat facility to check my documents had arrived, as was concerned when I hadn't heard anything. I found both excellent.
Applied online 26/6/22; and sent off attachments on 27/6/22
Received email confirming probate granted on 25/7/22 [4 weeks], and hard copy arrived in post about 3 days later. [Again, this seems to be fast compared to others - maybe we were lucky]
Step 4 - Collect the assets. Many bank accounts will transfer balances of a few thousand without grant of probate, so we had begun this process earlier. Larger sums need the probate granted, and of course if you are selling a house. We were advised by our estate agent to only market the house once we had applied for probate. We had everything ready to go, so that once grant of probate came through it could be marketed. I initially thought we'd set up an Executor account to collect the assets, but most banks do not have them anymore, and I couldn't see the point. Other beneficiaries trusted me, so we used a dormant bank account of mine as the account for anything related to her Estate.
Step 5 - Prepare final estate accounts - STILL TO DO
Step 6 - Report estate to HMRC - STILL TO DO
Step 7 - Pay out - STILL TO DO