Next and Bank account payment by cc then transfer?!

isthisfree

Hello!
I've asked a similar question before but have confused myself!
I've just managed to get 0% BT for 19 months Barclaycard and have made one transfer from Santander card. I'm also thinking of doing the following but don't know if I can- please advise!
Pay Next balance with HSBC card (currently empty as I've just asked for replacement one to be sent through for this purpose), then withdraw £600 cash (over 2 days) on HSBC card (to pay into current account to clear overdraft), then transfer HSBC balance to Barclaycard so no interest on Overdraft or Next account.
Is paying a bill like Next with c c counted as a cash withdrawal or normal transaction?
Will HSBC allow me to put the £600 cash into account when its obvious it's come from cash withdrawal? (this might be a stupid question?!)
Any advice gratefully recieved!