Got to be Pamporovo....... it's got the Snowshack, best boarding shop and tuition centre in Bulgaria............ and all the people there are British so they will fully understand your needs.
As i would like to remain as unbiased as possible.. Its difficult. I know and love Pamporovo the best. Honestly though for a first time boarding holiday i have to say Borovets or pamporovo, not bansko.. Go to Bansko next time, after you have developed your skills on a board more (it is for intermidiate to advanced). Bear in mind Apres Ski/boarding is a big part of a winter sport holiday.. Borovets or Pamporovo will always come out on top. Good luck with your decision, Cheers