wheel offset? help needed

[Mr Deano]

Hi guys, first off, Thanks for reading!!

Basically, i've finally got my heart set on some rims and i'm not quite sure about what offset i need, the rims i'm after are 18s (Azev m) and come as 2x8.5"(235/40/180 front and 2x10"(2?5/35/18) rear, Ive phoned for info and i'm told these wheels are with a 45mm offset, i mentioned i was also trying to fetch my rear wheels out (not under but closer) towards the arches.

Is a 45mm offset the correct offset for this mod? also, what are the appropriate tyre sizes?

Also, is there a problem with brake clearence (uk spec brakes)?

Any help would extreamly greatful

Cheers