There is only one bit of advice I can give you mate and this is it.

On a job of this size and situation, as you dont appear qualified there is only one course of action>>> Get a qualified engineer to complete the job or maybe one of our AAT electrical members might be willing to complete it for you.

Let us know where you are and maybe we can put you intouch with a qulified spark in your area. Or leave a message in the I need section and maybe an engineer will contact you. Obviously there will be a charge or charges, but the engineer will tell you their fees before starting the job.

Regards T