Determining land value after subdivision?

We have the possible opportunity to develop a block of land in Melbourne's eastern suburbs. Is the family home (Californian bungalow) at the end of it's life span.
Block is long and thin (15.24 x 44 - approx 671 m2. ) The plan being kicked around is a side by side subdivision, we are gifted one lot (we pay stamp duty any CGT and all development costs) and fund both builds (we live in one, mum lives in the other).
Have read through many posts on the forum and learning lots quickly. So may have many questions.

At the moment the land value is approx 1.3 mil . Based on $2000 per m2 .

How do we ball-park what the subdivided land value will be, each being 335 m2 ?
Similar small blocks are being purchased (one around the corner) in the 1.0-1.2 mil vicinity and house knocked down for rebuild.
Is this a valid estimation for us to use in our number crunching for value of each block post-subdivision?

Thanks in advance for assistance

 

You need to find comparable settled sales of similar blocks.

 

You will find it pretty hard to find comparable land only sales of 6.7m x 44m land.

Either get a real estate agent to do a free appraisal or do a back of envelope assessment your self. (Good to do both).

Best way to do your own estimate is find comparable new townhouse sales and subtract the improvements and a little profit margin.

I.e based on the suggested land value in your area people probably spend about $12.5k-14k/sq on a townhouse build. So guesstimate the squares double storey single garage 3bed 2living 2.5 bath say 28sq = $350-400k
+ $15k blinds lscape fences letterbox clothesline
+ $50k of finance & profit/risk margin
=$415-465k

 

Thanks @Caltan . That's really helpful.
You are correct - there isn't vacant land in the area to make comparison with.
Managed to find a block of similar dimensions with a dilapadated house that was demolished - sold for $855 000 in 2010, and a block with derelict house 10m x 45 that sold for 1.3 mil last year. (Both in nearby streets)
Our block value probably sits somewhere between here. Conservatively, maybe 900 000?
Your figures for townhouse build are very useful!
Thanks