cold, goal, soul, hole... Vs. code, goat, so, home...

Hi!

I'm interested in English phonetics and I'd like to ask someone living England about the vowel in these words above - do you use the same diphthong in all of them, or does the vowel before /l/ (e.g. "cold") sound a bit different (more like the American one)? If so, is it an RP feature or not?

Thanks in advance