ive just bought a second hand set of 16inch wheels with 205x45 tyres 4 my datsun 1200 ute the problem ive got is that they fit the back no worries but not the front got any ideas? it looks like i need about a 30mm spacer to clear the struts i know there going to sit out the guards but i was going to run flares aswell?

Yes they need a 30 mm spacer.

205s are too big to fit under the front sheet metal without flaring the guards. You might be able to simply "roll" the guard.

if i run a spacer on the rear as well can i run a 225 tyre on the rear?

also would i be better buying a 35mm spacer or 30mm for the front?

25 or 30mm bolt on spacers would be best, 35mm is way too wide.Loads the hub bearings up too.