“Sultan vinegar” sounds like “salt and vinegar.” A riddle was printed in The Guardian (London, UK) on June 28, 1989:
 
Q: What crisps are named after an Arab ruler?
A: Sultan Vinegar.
 
     
28 June 1989, The Guardian (London, UK), “Geddit?,” pg. 20, col. 5:   
What crisps are named after an Arab ruler?
Sultan Vinegar.
(5 pounds to Rachel Jones)
       
Google Groups: rec.humor
Christmas Cracker Jokes
TheCrypt1
12/28/98
Q: What’s crunchy and lives in the orient?
A: Sultan Vinegar crisps
     
19 May 2001, Evening Mail (Birmingham, UK), “Weekend Life Mag,” pg. 32:
What crisps are named after a Middle East ruler?
Sultan vinegar!
 
Google Books
The Sleepover Joke Book
By Sandy Ransford
London, UK: Puffin Books
2003
Pg. ?:
Knock, knock.
Who’s there?
Sultan.
Sultan who?
Sultan vinegar crisps are my favourite.
   
21 December 2003, Sunday Telegraph (Surry Hills, New South Wales), “The Funday Telegraph,” pg. S11:
Which Arab invented flavoured chips?
Sultan Vinegar!
     
Twitter   
Summer of ‘86
@diary1986
Holiday Fun Jokes page:
Q: Which Arab invented crisps?
A: Sultan Vinegar
8:36 AM - 25 Jun 2010
 
Twitter
Proper Facts
@Proper_Facts
The leader of the crisp eating nation of Brunei is known as Sultan Vinegar.
7:52 AM - 24 Jan 2015
 
Twitter
Debbie McGee
@thedebbiemcgee
Who was rich and famous and invented flavoured crisps?
Sultan Vinegar 😊
3:29 AM - 6 Feb 2016
 
Twitter   
Richard Wadwell
@wadwellington
Replying to @tara_snow
Oh lord, “salt and vinegar”. I Dare say they do these posh crisps in “Sultan” vinegar ...
4:31 PM - 22 Feb 2019
 
Twitter
Jim McClenning
@jimbomcc
My mate just told me that there’s an Arab trying to buy up all the fish and chip shops in Britain - his name is Sultan Vinegar.
4:07 AM - 6 Mar 2019
 
Twitter
Ian
@ianbub73
Replying to @channel5_tv
It should also be pointed out that crisps were invented in the middle east, by Sultan Vinegar.
9:13 AM - 25 Mar 2019
 
Twitter
🤣 The Dad Joke Man 😉
@DadJokeMan
I bought a bag of crisps in Brunei.
They were Sultan vinegar…
12:47 PM - 5 Jun 2019