Cant help with what it is, but I see there's another one in the back ground.  

From the horn i am going to say a Indian....?

You could be correct. Looking closer at the pic, Front end looks more Harley than Indian. The front fender light threw me but some early Harleys also had a fender light fitted

Really hard to tell from the pic. If it was Indian you should be able to see the light/thing mounted on the front guard as well as the spring holding apparatus but you cant really make it out. There is something on the front guard, might even be the sheilas underpants judging by the smiles. Great picture.

Not sure what the family connection is, but I scanned an old large format negative to find this.

The bloke in the sidecar appears in other old family photos, possibly Daylesford, Victoria around 1933.

It's a J model Harley, no front brake so pre-1928.

Very cool pictures there Postie! It’s a V model more than likely a VL (1200cc-74ci)they were produced from 1930 to 1936 and were then replaced by the U model.The D model you mentioned was a 750cc(45ci) “Solo model” produced until 1932 and were replaced by the”R” model,same engine capacity 750cc(45ci).By looking at the picture,the difference between the R model and the VL (at a quick glance)is that the VL springer had tabs in the front legs to attach the front guard with the bolts for the front guard going in a vertical position.The other detail to suggest it is a V model is the Goulding sidecar fitted on this bike.If it was an R model (750cc-45ci) it would of been fitted with a “Goulding LS29 model “side car. A much lighter sidecar easily recognisable by its pointy boat shape nose like.”Goulding” used to be the american sidecar manufacturer used by Harley but also Henderson,Indian and other brands at the time,there was also a Gouding sidecar manufacturer in Australia,not sure if it was the same manufacturer though. As for the year...in 1932 few changes in cosmetic designs,the fork mounted tool box under the headlight was replaced from the round shaped one to an oval shape like you have in the picture,with the new electric horn design. As it is a very nice black and white picture that i’m sure you’ve enlarged and put it for everyone to see when visiting you , unfortunately you can not see the colour scheme to pin point the exact year.That would leave us with..in my view... a VL model circa 1932 to 1936 give and take a few oil changes... lol.