Answer:
Past Perfect Progressive
Step-by-step explanation:
Although there is no underlined phrase in this text, the only verb phrase is "had been winding up". 
Past perfect continuous tense or past perfect progressive is a tense that shows an action started in the past and continued until another time in the past. 
Its structure is as follows: subject plus had been plus present participle of verb (verb + ing). 
So, “had been winding up” is a past perfect progressive tense.