What have you done today with your Austin Seven

[A G Wood]

...and here not allowed for w.o.f despite being used in many cars originally and very strong...
I don't want to be That Guy, Bob, but that isn't actually 100% correct sorry.
I won't bore everyone with a cut and paste but have a look at the on-line VIRM (the guide for WOF inspectors for non-NZers) 
Section 9 "General Repairs" section 9.2.7 "Reasons for Rejection".
In fact, brazing is  I-CAR compliant in areas specified by an OEM procedure.(emphasis mine)
 see < https: //rts.i-car.com/collision-repair-news/mig-brazing-what-is-it-why-should-i-use-it.html> 
**the link won't post in its correct form,  so if you want to look at it you'll have to remove the added space between the colon and the double slash
Also look at the  'Applicable Legislation' tab on 9.2.7 what the LTR has to say about date of manufacture and material compatibility.
I would suggest that provided the process of a brazed repair, even a traditional non-MIG one, is done in a tradesman like manner, in the correct application,  and there is no manufacturer's guidance available it would be fine for a WOF...