HI I've got a 2013 mk7.5 1.6TDCI. Would the 17" x 8" fit ok on my car and what would the difference be over the 17x7's? other than 1" width, Tyre availability maybe? What tyres would best suit the car. Running standard suspension.
Thanks in advance

Have you checked the offset of the new wheels?  The offset will dictate where that extra inch ends up with regards to potential rubbing on suspension or arch.  If the offset is roughly the same and the car isn't lowered then they'll probably be fine.

You'll need at least a 215mm wide tyre on an 8J rim.  You could get away with using either 215/40/17 or 215/35/17.  There isn't a perfect radius equivalent to 205/40/17.  The 35 profile looks very limited for tyre choice so I'd go for 215/40/17 myself.  Radius will be slightly larger so the speedo will underread slightly.

I'd incline towards sticking at a 7" rim with 205/40x17 which was the maximum standard fitment on the Mk 7.5. There isn't a massive amount of room in the Mk 7/7.5 arches anyway - the Mk 8 has a bit more room and that only goes up to a 7.5 rim as standard, even on an ST.

Apart from potential clearance issues, bigger wheels/tyres increase unsprung weight and drag which you really don't need with only about 95ps to play with.