Firstly the attached Tyresafe document will be of use. I carry a copy in the van at all times
In the 155/80 R13C you refer to, C means it is a light commercial tyre. The T and R you mention refer to a speed rating on a normal car tyre.
From memory of owning a 900kg axle Familia 310GT, you need search for a 155/80 R13C with am 83 to 87 load rating. You do not need to worry about a speed rating.
What you must check is how fresh the tyre is so ask for the manufacture date off the tyre wall.

Colin

The 84 rating is fine, but I do not recognise the make though. Having said that, it is not worth buying a premium brand tyre as it is not subjected to the same forces a tyre on for example the driving wheels of a car is, but I've usually gone for a name I recognise.
I recently used Tyres on the Drive for my car and will use them next year for the Eriba. They were bought out by Halfords and provide tyres for several internet providers including , I think, Asda and E-Tyres https://www.tyresonthedrive.com/
You may have to contact them directly by phone, but this could be to your advantage as you might be able to get the tyre dates.

Colin

I would be happy with the Hankook. We fitted the all seasons to my wife's VW UPas they were a best in test result.
Best way to jack up is, hitch the car up, raise the corner steadies, trolley jack under the axle. This way you are putting no weight on the corner steadies.

Colin