Used 2010 Vauxhall Zafira Life for sale near Slough

Hi guys I had my turbo and oil change did a month ago . Acceleration was a bit slow to kick in but was told this was normal . It has been driving good on but last 3 days the power acceleration kick is gone again up hill foot down takes ages to go from 20 mph to 30mph . I have only drive it 250 miles in local area and it I have not gone over 40pmh since repair as I did not hit the motorway yet. But last 4 days it’s taking a while to kick in 30 have to put my foot all the way down . I thought maybe I need to drive it a bit and the hissing noise was not so load before . Today I went for a uphill drive to try drive it out I went uphill long road and put acceleration all the way down it was Stuck on 20mph then all of a sudden at nearly the top of the road it finally released and the car started to feel normal again acceleration was back but the hissing sound isis in now Evan without pushing on the acceleration it’s driving good but a constant hissing like air being released or a vacuum . The cleaning light came on not sure what it is the turbo defo but it was repaired last month . Is it because I need to drive it or is it something else