[Sundae]

The host on Would I Lie is the exceptional Rob Brydon.
Who appears in Gavin and Stacey with a much stronger accent.

Go to the motherlode.
Watch the strong accents. Then you can dilute as necessary.

I spent about a week trying to work out the accent of a boy in a Kia car advert.
He only had two lines.
Eventually realised he reminded me of Susannah and therefore concluded it was Brummie.
She was horrified. She came from Telford!

(Birmingham to Telford 33 miles)

Or don't.
It's a fun game but I admit I'll only ever get the broadest of American accents.