Introducing hydrolysed formula for suspected CMPA

My nearly 7 month old has suspected CMPA and gp has just prescribed some of the hydrolysed formula. However, I’m really nervous about using it as I know that it’s rank and often babies hate it! He is combo fed and only has about 200ml a day currently but we were planning to up this a lot over next two months as I’m going back to work. So the last thing I want is to put him off bottle feeding!
Would it be ok to introduce it gradually by mixing it with his regular formula (premade aptimel) and gradually changing the ratio? I thought this might also help with the probable resulting constipation, as he had this terribly when we last tried to move to powdered formula. His symptoms have improved already with me going dairy free but obviously that won’t continue as we up his number if formula feeds.