Thanks a lot buddy, in that case I won't need to go find another similar engine. Happy that an expert can confirm! I did a complete service - oil+filter, air filter, Denso spark plugs, drive belt, cabin filter, brake fluid flush, clutch fluid flush, new clutch kit repaired the undertray and put new chimney u nuts and bolts, new calipers/rotors/pads on the rears (similar fate as my MK7 accord's seized rear caliper pistons), and an alignment (the camber on the LH rear is off by 1 degree so will see if it does anything much to tyre wear and decide whether to buy a camber kit, so far tracking is good). To be fair the car only had one previous owner who did all the servicing himself but never logged them.
A little side question: My only outstanding item on my list is the gearbox fluid which I have yet to figure out where the drain bolt and the fill bolt is.. do you happen to know if there's an image that can point those two out? (And I'd like to think it just needs the bog standard Honda MTF?)
Agreed, I will probably need a whole weekend to just take my time doing the valve check. I've done it for two of my previous motorcycles so I'm hoping it's not going to be too much more onerous!