Update: I made a temporary fresh OSX install to the 128GB SSD. So it should now be as simple as following your steps and then restoring Win 7 afterwards. So long as I can work out how to install the bootloader.
Bootloader can be installed either manually or with installer package. I'd recommend manual method (if Cahmeleon is used), as it gives you full control other the process. it is more complicated then installer method though. There are guides on both methods.
However, if I remove all partitions from the drive and then attempt to restore the OSX to the beginning of the drive, I get an unbootable drive. Booting from the SSD in UEFI fails and it just defaults to the next bootable device if finds (usually my HDD).
Could this simply be because I haven’t reinstalled the bootloader? You'll have to forgive me... bootloaders aren't my strong point. How can I do this without actually booting into OSX?
A sector-by-sector clone of a disk does the complete copy of all the sectors present in the disk (including bootloader part). When you restore only the certain partition, only the data in that partition gets restored.
Bootloader (Chameleon for instance) itself consists of few binaries - boot0, boot1h and boot (plus some other important stuff). boot0 goes to MBR. When you restore the whole disk, MBR is also restored, hence OS X boots as it should. When you restore only the single partition, MBR is not restored, only the partition itself gets restored.
There are two most common bootloaders for the OS X on PC - Chameleon and Clover. An important difference between the two, is BIOS modes supported. Clover can be used with both UEFI and legacy mode (UEFI is preferable). Chameleon can only work in BIOS/legacy mode (UEFI mode is not supported). There are many info on both (esp. on Chameleon). Both have installers and both can be installed manually. Again google/search the forum.
As you have MBP, you can create a bootloader USB pen drive. This USB drive would only have bootloader installed and would serve as a temporary boot device. Once this USB is configured and proved to be working, you could copy the appropriate contents (from this USB drive) to the SSD with OS X. The goal of this USB drive is to let you boot OS X from SSD without fist installing a bootloader to the SSD itself.Go to the full post