Look on the right of the screen - there's an indicator light that shows when you're under the hatch (the 'board ship' light illuminates). This is in the main HUD, not in panel 3.
It doesn't matter which way you're facing, can be forward, backwards, sideways - all that matters is that light and that you're stropped parked up there. As long as it's illuminated, go to panel 3 - board ship and your SRV is automatically orientated and taken aboard.
I'm off to bed now by the way but I'm sure someone else will dive in if you have further questions