Transmission problems in new (used) Tourneo Connect

I bought a 21 reg Grand Tourneo automatic from a dealership last week.  It has quite high mileage for its age (62k) but the vehicle is in otherwise really good condition inside and out so appeared to be well looked after despite the mileage.  When I took it for a test drive, I thought some of the gear changes at lower speeds were a bit jerky but thought perhaps it was just the nature of the vehicle.  I couldn't tell properly as there was a lot of traffic about and it seemed intermittent anyway.  On the hour's drive home it became more apparent .  I took it out again the next day and it was obvious that something wasn't quite right - there was a lot of jerkiness/shuddering from some of the gears, so rang the dealer and asked them to book it in for an inspection but they couldn't fit me in until the 14th.  

I used the car again the following day, it wasn't too bad on a ten mile journey out but on the way home the gears were quite bad, and then the engine light came on.  So I decided to return it to the dealer as soon as I could get a lift back which was the next day.  They now have the car and I;m waiting for them to get back to me with their verdict.

I had assumed the car had a Powershift gearbox and from what I've since read about it, wasn't going to risk future problems but have now discovered it has the 8F35 auto box from a label inside the engine.  I'm really disappointed as the car ticks all the boxes but don't want the prospect of potential expensive issues.  I should be covered by the 30 day statutory rights so can hopefully get a full refund without problem.  Since this is a newer transmission, would I be unwise to stick with the car and am I equally as likely to get problems (the car only had partial service history and there is no evidence of any gearbox servicing).

Any advice and/or experience of this type of transmission?