Don't want to say 'best' as it's a subjective thing, but these are SUPERB:-

Allan Taylor (Moody and Magnificent!)

Jez Lowe

Kathryn Roberts and Sean Lakeman (both Trad and Contemporary)

If'n you're a Bluesperson, try Emily Druce. (Do we call blues 'Traditional' or 'Contemporary'? As a lot of it's from the 20th Century, I guess it can be counted as Contemporary?).

A young lady from Lincolnshire - Miranda Sykes (solo and with her excellent band 'Firebrand', fantastic voice and again falls into both camps).

And, of course, the aforementioned Harvey Andrews - songwiter and performer of the highest order.