Freelander 2 (LR2) Wheels and tyres

Does anyone know if I can replace my 235/60/18 wheels and tyres with 235/60/17 wheels and tyres and any effects doing this might have please ?
Reason is I have just been offered a cheap set ?

It'll alter the gearing, which will reduce MPG and your speedo will over-read. You'll also need to inform the insurance company, as it's a modification outside of the factory spec. This normally pushes the insurance premium up, so counteracting any slight savings on tyres.

Besides it'll look silly with tyres that are an inch smaller in diameter.

Thank you, much obliged for your quick response, was a bargain though

Recommended tyre sizes are printed on the drivers door pillar.