Hi, I'm in the process of changing my front discs/pads and the originals are the ones been removed. It looks like the disc and wheel locator look like one piece. Do I need a spline tool to remove? Also I've bought mintex brakes which don't have a wheel locator...is this right? 

It looks like you will need a torx bit to remove the countersunk screw that retains the brake disc . 

The centre that locates the wheel is part of the hub not disc.

I would gently suggest that you don't know how to change your discs and pads. They are too important to get wrong, get someone to help you who has done it before!!

Torx bit + hammer and impact driver. Have fun getting the calliper carrier off aswell.

if your not sure about anything atleast get some one who is to check it.

The large splined bolt in the centre, and the spigot  around it that the wheel sits on, are part of the hub. You don't need to touch those.

You do need to remove the small screw that has a torx socket head, which is sat between the two bolt holes towards the left of that pic.

Once that's out, the disc will come free of the hub (*after*you've got the caliper and pads off, which you need to do first). It may take a bit of a knock to free it from the hub.