Fixing Cistern to wall

Hello all, I've just finished tiling my bathroom. I left the plastic bolts on the wall for fixing the cistern to. Now I find that I can't get the cistern to locate on these bolts for the plastic nuts because of the tiles!
The armitage shanks cistern has two holes in the porcelain - I am tempted to just screw fix through these on to a timber baton, but should I use a plastic bolt system and if so where can I can these from?
The amount of time I have already spent changing the syphon/handle/ball cock/blanking plates... I could have just got a new cistern...
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