Glad you got off with such a minimal impact!
Aldcoll, the "better spec" unit may have been the Environmental Potentials EP-2050
, possibly with the additional EP-2750
ground filter. I had these installed in my mains panel back in 2011 when I added my dedicated audio sub-panel and it's been silently doing its thing ever since without issue. I've had a couple electrical incidents since then, but nothing inside the house has been damaged. (No direct strikes, thankfully!) The EP-2050 hangs off the bottom of my panel (which is located on the side of my house) and the EP-2750 is inside the panel sitting at the bottom.
By the way, if you're going to rework your mains panel anyway, another thing to consider is to move any circuit supporting an electric motor (washer/drier/dishwasher/furnace blower/refrigerator/etc.) or half wave rectifier (lots of things, but often heating devices, such as pool and hot tub heaters, etc.) on the leg opposite of that from which your audio circuits (or other similarly sensitive devices) draw power.
One other thought... when I upgraded my home networking gear to use switches that already had optical ports built in, I had some TP-Link optical Ethernet media converters left over that I was originally going to sell. Then I decided that I really would rather further protect all of that expensive networking gear and everything connected to it, so I put them between my cable modem and the router, thus severing that electrical connection and ensuring that any surge coming in over the cable line can now only damage the modem and nothing else downstream. Food for thought...