Woodridge Cruisers

I'm booked on a TA from BCN in October and I starting thinking about when to apply for the VAT refund... actually in which port. My cruise departs BCN with stops in Malaga, Cadiz, and Tenerife. I thought I read somewhere that you apply for the refund in your last port of call if all ports are the same country. My last TA stopped in Tenerife; however, I don't recall seeing a VAT refund processing office/kiosk at the cruise port. Any insights as to when/where to apply? TYIA!