@M4v3r1ck - First time around, we did as follows:
8 weeks = Booked an early scan privately (also had our NHS booking-in apt).
10 weeks = Booked an IONA test privately.
12 weeks = Had the usual NHS dating scan (and checks for abnormalities).
The 8-week scan was to convince us it was real before we paid £400 for the IONA test - which we wanted before the 12-week scan (as it can take a while for the NHS abnormalities test results to come back).
We wanted to be able to tell people, as it was getting tough to hide.
We feel the same this time, but more nervous!!! The NHS has offered an 8-week scan because I'd already been referred to the fertility team. I may also have extra scans because I'll be classed as 'high risk', under consultant care (simply because my first baby was born via c-section). If it gets that far.
I took another cheapo test today (!!!) and there was a very definite line (darker than 6 days ago), so that's reassuring (although not out of the woods yet).