Aloha Kirk,
I's sorry to hear about the damage to your car.
A few years ago, a Nissan pick up truck turned left in front of mt TR3A. The Nissan bumper caved in the left front fender and crushed that side of the front cowl and grille. Fortunately, the truck bumper was higher than the TR3A frame so the chassis was not hit. The car was towed to a collision repair shop approved by my insurance company (Hawaii is a no fault state). At first they were leery of the job, but I assured them that new replacement panels were available. They did not want to have deal with salvaged panels. They ordered the parts from Moss Motors using my catalogs. It took three or four weeks for the parts to arrive and then they began fitting them. Two guys that were probably in their 50's or 60's were assigned to repair my car by the shop. It was probably another three or four weeks before the job was done. They were several minor adjustments they made to the new pieces and several trial fittings to make sure seams matched, the door gap was consistent, the grille fit into the cowl with out any gaps, etc. The guys really took pride in their work. I visited the shop several time and they were happy to discuss with me the work. As I recall my insurance company paid about $7000 for the work. My insurance company sued the other drivers insurance company and prevailed so they recovered the money.
Bottom line, new panels are available but some work will most likely be needed to get a good fit. I suspect most collision shops will want to deal with new panels, but may not want your work. They seem to prefer jobs that are quick turn around, in and out and collect the money. However there are still auto body craftsmen out there.
A picture of the car after the repairs is in the member's car section in the Triumphs, look it up under M for MGTF1250Dave.