This may or may not help... You can call Terry's Jaguar and ask the experts if the British Leyland colors for Jaguar also applied to the Austin Healeys.
CODES by Paint Manf.
1= British Leyland
2= Dupont Lacquer
3= Dupont Enamel
Cream(Old Eng. White) 57-70
1. N/A -- 2. 8313L -- 3. 8313A
Old English White 71-79
1. BLVC250 -- 2. 32501L -- 3. 32501A
I didn't have the link, I hope that my homemade chart makes sense. I know that there were very few colours that weren't used by just Jaguar, MG, Triumph, etc...
My 1975 XJ6C is Old English White, therefore I would have a touch-up kit made to DuPont's number 32501L if my paint was lacquer.
I would imagine the code for your Healey is 8313A in DuPont enamel and most shops would easily be able to duplicate a sample for you.
Keep us posted on the outcome, and check with Terry's, their website is
https://www.terrysjag.com. There phone is 1-800-851-9438.
Best Regards,
Brian