I don’t think that Meetens ever held much ( any?) Aspera / Tecumseh stuff. Also, it’s my understanding that Meetens have recently sold out to L & S Engineers. I’ve never actually looked at the L&S site for Tecumseh stuff but it may be worth a look. Another supplier worth a look is JAPG. If you are really desperate, try the USA but by the time you’ve paid shipping and UK duty and clearance charges the costs will build up.

When Tecumseh UK closed down all their parts stock was bought by Peter Elliott who trades as Meadowbrook Enterprises and has an eBay presence. However Tecumseh’s inventory would have comprised mainly parts for current products. Further more it is roughly ten years since Peter Elliott took over the stock and that will have been depleted over the years.
As far as I know Jon Cruse is the most likely source of anything that’s left and your comment re his health may account for a recent unanswered email enquiry of mine.

Old petrol Flymos used variations of Aspera, Tecumseh, Tecnamotor and Kirby Lausons, all using similar ignition parts branded, Phelon, Ducati and Scintilla – Most interchangeable. Pre Covid a beat up old Flymo could often be bought at our local collective auction for less than £20.

Gaskets are reasonably simple to make diy and I have a friend who can laser cut perfect ones, but he needs a pattern. However he can clean up a tatty one on the ’puter before producing a perfect result. I’m not volunteering his services as it’s not his main job and he has the kit for a different purpose, but there are probably others who can.

You list coil, condenser and points but are you sure that you need them ? I’ve rebuilt many Aspera Engines over the years and other than an occasional condenser I don’t recollect much need for coils or points.