I have run my vehicle on 17's for nearly a year.
I dont know the tyres you have, but as long as they are 'e' marked then they are suitable for use on our roads.
Off road might be questionable as many brands in that size are manufactured in a 95% on road pattern.
Having said that with TC, 4 wheel drive and a light vehicle many road tyres perform well on wet grass / mud.
I was surprised with my Goodyear wranglers a few years ago when I had to pull a minibus and trailer off a sodden campsite - I thought i would spin, but not a murmour and they were all on 2 - 3 mm!!
Regards,
Steve