I had a fitting by a PGA Professional. He recommended;
Mallet Head,69 degree lie angle,30-45 degree toe hang,33 inch shaft,1 degree loft. Can you recommend how to go about acquiring such a putter? Thank you.
Wow - that's what you call a precise set of technical requirements! I assume, since you're asking, that the PGA pro who did the fitting can't supply you with one (or would charge the earth for doing so...)?
My advice to you would be to locate a top-quality clubfitter in your area who has the equipment necessary to adjust putters. This needs different kit than adjusting irons and fitting woods, so make sure you ask direct questions, rather than simply assuming he or she will be able to manage this.
Once you've found a go-to person like this, then you can find the mallet style you like (by all means start here: https://www.best-putter.com/mallet-putters.html). It's the head style that you're really looking for, because the other characteristics your PGA pro has recommended can be altered by the club fitter.
I'll be honest with you, I'd probably pick up 2 or 3 putters you think you might like the look of on ebay, get them all altered to the spec you've been recommended and then decide which one you like the best! They will all feel different when they're set up.
Any you don't need at the end of the progress, you'll be able to re-sell for more or less what you paid for them on ebay, and you'll have a putter in the back that you know you really like!