I recently submitted online VAF4A form for UK Settlement Visa (married >4 yrs). I have a query regarding my surname.
This might be a bit convoluted, so bear with me!

(I am using fictitious names)
I am a USC.
My maiden name was DOE.
I then married JONES, but we divorced.
I then married BROWN, but we divorced.
I then married UKC SMITH and we are still married.
After I married UKC SMITH, I resided with him
briefly in the UK. During that period of time, I used his surname. My NI number was in the name of SMITH; my LLR (long since expired) was in the name of SMITH. I never changed anything else of mine (credit cards, driver's license, etc.) to SMITH.
When we moved to the US, I did not use SMITH because everyone here always knew me as BROWN. I had been Mrs. BROWN for 25+ years. My US passport was still in the name of BROWN. Everything here in the US was - and is - still in the name of BROWN. I just didn’t want to change everything over to SMITH. (SMITH is so
boring compared to the surname I actually use in reality.)

Are you still with me?
When we return to the UK to live, I wish to be known as BROWN and not SMITH, and there’s no law that says I have to take my husband’s surname.
I filled out the online VAF4A using the surname BROWN, although it did ask if I had ever been known by other names and I listed them all there.
Think this surname thing is going to create a problem? The only issue I see (after my move back to the UK) would be that my NI number is in the name of SMITH.
Hopefully, the above explanation in my letter accompanying my VAF4A packet will suffice.