Get your taxes done using TurboTax

Yes, you should go ahead and file the substitute 1099-R and create the Form 4852 since a UK entity would not be issuing a 1099-R to you.  The IRS won't be giving you the Form 4852 to use since they are only issuing that for American Entities.

You can follow these steps to fill out the information in the 1099-R section of TurboTax.

1. In the Income section, go to Retirement Plans and Social Security section and click the Start (or Update) button to the right of IRA, 401(k), Pension Plan Withdrawals.
2. Click Add a 1099-R
3. Click Skip Import at the bottom of the next page
4. Click on the 1099-R tile at the upper left, then Continue.
5. Enter the 1099-R provider info.  Your UK plan provider with not have a Payer's TIN, so you can just enter 99-9999999 there.  Click Continue.
6. Enter the total distribution in US Dollars in Box 1 and the Taxable amount in 2a - these will likely be the same amounts
7. Enter a Distribution code of 7 in Box 7
8. Click Continue at the bottom of the page
9. On the next screen - it is not an IRA, so click No, the box is blank
10. Click None of the above for Where is your distribution from?
11. It will be a Qualified plan since it is a pension
12. You can click "I Need to file a substitute 1099-R" on the next screen
13. On the next screens you will give details about how to calculate the substitute amounts, efforts you made to get a 1099-R 
14. You can skip printing Form 4852 if you plan to e-file your return.
15. On the next screen, you didn't roll over or convert the money
16. For Periodic Payments click Yes if you received the payments on a regular basis.
17. Click Yes or No as appropriate for "Did you start getting these payments in 2025?"
18. For Annuity Information click if the total amount was used to determine the the tax you paid on it.