Discovery Sport Transmission Fluid Change

Hi, I have a 2015 Discovery Sport 2.2 with ZF9HP48 9-speed transmission. The car has 55K miles on the clock and is going well, however, I am now considering an ATF flush on the transmission. On my previous Freelander 2 I did a series of about 3 quick flushes to dilute the current ATF and wondered if any one has done this on their Disco Sport and what ATF did you use ??
My main concern is mixing a recommended synthetic ATF with the LR factory installed ATF that will already be in the transmission, any other suggestions would be greatly appreciated.

Use fluid that meets the LR spec. the same as a LR dealer service department does, service departments are free to use what brand of fluid they wish. Ask what brand of oils they use when u take it in for a service.

So what the issue do u have with the auto box that requires flushing.?

No real issues, the transmission seems to move through the gears with no problem. Just felt that I may keep this car for quite a while and thought a service now would keep the transmission in good order. I do have a query about recommended ATF changes, the local Landy Dealer Service says 100K miles or 10 years, my local auto tranny specialist in Hampshire says 50K miles. They want £270 + VAT for a full system flush, Dealer wants £900. What do I do ??