Buying a property with subdivision potential

Hi all,
I am looking at a property in another state.
The block is over 700sqm and indications are that council will allow a second dwelling on the back of the block , pending sewer...
I dont yet have the sewer diagram (I have submitted a query to the local water board) . The local council believes the pipes are between 10 and 14m back from the boundary - which would probably work out ok if its between the two dwellings...

I am thinking of sending the following - can I ask your opinions please?

Hi xxxx,
We would like to submit an offer for the property.
Subject to the following conditions -

-Subject to building inspection. Also the following - the seller warrants all electrical,gas, plumbing fixtures and fittings shall be in good working order at the time of settlement, at settlement date, should any repairs required to meet this conditions not have been effected. the seller authorizes the estimate cost of these to be deducted from the settlement proceeds.

-Subject to provision of sewer diagram (illustrating suitable position of sewer pipes to allow a second dwelling to be built at the rear of the property)

-Subject to finance.

The offer is for the amount of $xxx

Yours sincerely ,
D and J xxx
I have just done something similar except my issues were with fire rating and environmental issues.

We just wrote up a normal offer document with a clause to the effect ' subject to fire and enviro report to satisfaction of the purchaser'

Offer was accepted and conditions about to be cleared within 7 days.
The more "subject to" conditions you put in your offer, the less attractive it will be to any vendor. Depending on the market conditions where you are buying however, if quiet, you may get away with it........not so much if it was Sydney :)

Also, unless the vendor & agent know that the property may be subdivide-able, I'd leave any reference to that out of your offer (as you may be alerting them to something they were unaware of, and the asking price may rise).
Thanks for the replies. The property is not in NSW.

I have slightly changed it. Please let me know what you think..

Subject to building inspection report to satisfaction of the purchaser and that all electrical,gas, plumbing fixtures and fittings are in good working order at the time of settlement.

-Subject to finance.

-Subject to current sewer pipe position being to the satisfaction of the purchaser. Pending report from xxx(water board)