Update on the matter: I now have my car back from Fensport, after they did an amazing job at fixing it(and upgrading)!
They looked at the above videos and I told them what was happening, so they advised it needs stripping and proper looking at to see what exactly is broken. They had a good second hand engine available that had done 45000 miles if I just wanted to do a quick swap and save some money - but I wanted to upgrade some parts and kept that as a fallback option.
So initially we got to the following items:
New genuine crankshaft
Genuine conrod and main bearings
ARP head studs
Brian crower forged conrods
Kelford valve springs
All fluids for running in and final
2x oil filters
Toyota genuine coolant
Oil system improvements to dramatically improve oil pressure
Fensport custom oil pickup pipe
We went down the route of forged rods only as Tom is running this on his GT86 and he is hitting 460bhp on his daily very comfortably, though the advice is to not go higher than 500bhp.
They removed the engine and got majority of it stripped down and find that it is worse than anticipated. The insides had nasty charred black coating and the oil smelled burned.
The bearing on cylinder 1 conrod had somehow welded itself to the other bearing causing heavy crankshaft damage. It looked like the engine has been running like this for quite a while like this and remnants of bearing material can be found throughout the engine. Piston oil scraper rings have been blocked by burned oil and carbon preventing it from reaching the sump. They needed to strip and clean the engine considerably more than expected and also inspect the heads to see if there is more damage to the camshafts or carriers.
Next step was to actually see what was salvageable from the engine and what is not. Depending if the damage is beyond usability with stock pistons, we potentially have to look at getting a brand new shortblock from Toyota which would be cheaper and less time consuming.
Luckily the cylinder heads were decent apart from light scoring on the camshafts and journals, but that seems to be very common in these engines and is no cause for concern. Unfortunately the block and pistons are no good at all and can not be re-used. I could have gone for more forged internals but as I'm not planning to go beyond 500bhp I opted for the brand new short block. Whilst we were waiting for that to come in, they built the custom oil pickup ready for the new setup.
Once the shortblock came in it was quickly getting rebuild with the new interals. You can definitely see which part of the engine here is nice and shiny!
I've had her back for a week now and runs like an absolute dream, I am happy I went down this route and looking forward to many more miles and future upgrades with Fensport.
Big shoutout to the team at Fensport for the amount of updates and pictures I received during the process including invaluable amounts of information on parts/upgrades/issues etc. Not to mention the few saturdays they came in to work on it due to having more issues than expected.
Happy to say I will definitely going back to them for anything else.