For visa...I think you should worry about expiry date not the starting. and as per my understanding it is one year after the medical (Any correction to my understanding will be appreciated)
How to do Medicals w/out the forms?
Usually we need to do our meds thru the forms [IMM1017] supplied by our VO [the concerned CHC]. However, there could be reasons for doing the same WITHOUT them. Eg. the forms are lost, the CONsultant is withholding them, forms r somewhere & u r somewhere else etc. In such case, we 'can do the meds w/out the forms' too. Here's how:
1. Email CHC again to re-issue u the IMM1017 [med forms]... if time permits.
2. If not, Contact a DMP for an appointment.
3. Inform the DMP, in advance, that u want to do the meds "w/out" the forms.
4. They can get your meds done by 'creating' those forms* for u.
*Note:
- All DMPs have those 'blank'* forms.
- All they need is an 'authority' to do so. If u have the CHC's email - it would suffice.
- If u don't have an email from CHC, yet the DMP'll be happy to assist u [read they want the money].
- They'll need your File No. + 2xPhotos to prepare the forms [specific for u].
- U need to show the DMP your original Pps & pay the DMP's Fees [of course].
Important: If u do not get the CHC's nod to do the meds, remember the meds expire by 1yr & your visa/s will be valid till that period 'only' [except if anyone of your dependent's Pps expire before that, then it'd be earlier]. So, doing the meds early could be risky - as it might offer u lesser time to 'land'. If that's Ok with u, plz be free to get the meds done earlier.