Interesting detective work between you all 
To the casual observer, the connection between Nats Padthai restaurant and Nat's Thai Spa is suggested by the name, style and lettering of the signs above both places. The connection to Thai Star Relax across the road is a bit less so. There has been very little reporting about these places over the years (Wakey's being the exception) and it has never been clear to me what the business sense is of having two places so close, both hugely exposed and indiscreet.
The restaurant never seems busy, nor does one seem to see people entering or leaving either of the massage shops.
But one assumes the money must be coming in from somewhere if she's expanding 
Whilst i am unsure, it is my understanding that 'Lanna' is Tanya's and that Nat as no involvement, however, a few weeks back another Thai girl had indicated that Nat wanted to concentrate more on the restaurant as the massage shop did not earn enough
Maybe the lack of guaranteed extras is the reason for poor earnings at Nats massage shop, i do recall Dee (Dee Dee in Agbrig Wakefield) when she first opened saying that extras were frowned upon at Nats, Dee, prior to setting up on her own, did a spell at Nats
Same with Anna at TSR, she once told me that she worked for a while at Nats, which only suggests to me that Anna must have thought she could offer/earn much more at her own place even so Nats
As JM eludes to, the reviews for Anna's are strangely absent, i do know that she can get pretty busy, though she does often have availability as she tries to not take back to back bookings, ok she isnt the prettiest where Thais are concerned but she aint bad at all and whilst MMV she as never declined any my requests for extras
As for Nats Pad Thai, i have been many times and the place has always been busy, that said, i am talking Thurs, Fri & Sat evenings, always found the food good and the karaoke at the end of the evening to be interesting, for want of better words
If any of the regular singers are reading this, then please accept my apologies, i cant sing either