Hi Ian,.
If in doubt, check in China - aliexpress
Their fabrication is getting better all the time!
I've probably had 25-30 orders of varying things,
pcbs,passive components, connectors, transistors, old .like bbd's and opamps, and assembled modules.
All been good with the exception of some crappy connectors, but hey! - I've had crap from closer to home!
A lot, if not most stuff is fab'd in China, shipped over and re-badged anyway!
Only down side is shipping can be up to 2 or 3 months stated. Funnily enough, my last order has still to arrive
and that was 5 weeks ago. Somethings prior had been delivered in 2 -4 weeks, and up to mid Dec some orders
were landing in less than a week!!
Here's the link -
https://www.aliexpress.com/wholesale?catId=0&initiative_id=AS_20190122143312&SearchText=lm723cn+voltage+regulator
Oh!! - also - can be stupidly cheap!!