Toilet waste connector

FreeBear

GDB2222 said:

I have a standard pan connector. This one 
https://www.screwfix.com/p/viva-slinky-fit-flexible-straight-wc-pan-connector-white-240-500mm/120hr

You want/need something with a smooth interior surface. Any ridges is likely to catch toilet paper and poo.

Are there any makers marks on the spigot or the fitting that was removed ?

ThisIsWeird

Have you bought your new toilet yet, GDB?
If you have, then position it where it'll be - complete with cistern - so you can actually see what adaptor is needed to join the two. Some 'straight' adaptors are eccentric, so can compensate for misalignment by simply rotating them. 
If 'no', then make a side sketch of that collar, and add all the dimes - clearance from floor, height to centre, etc, and then ensure any new loo is going to make your life easy.
To fit inside that collar, I expect you'll need the correct gasket, which will be either one designed for that specific fitting, or possibly one for a clay sewer pipe.
As asked before - check the outside of that collar (and the inside too) for any embossed markings that'll indicate the make.
But, to confirm - the internal diameter of that collar is 6"? And how deep?
Similar to this, but I suspect not quite: https://www.diy.com/departments/6-to-4-internal-pipe-reducer-to-fit-inside-160mm-underground-drainage-and-reduce-down-to-110mm-4-flexible-rubber-boot-reducer/5060718516915_BQ.prd

GDB2222

That looks just the thing. Thanks so much for finding it. I had no idea what I was looking for or whether it even existed. 

I wonder whether there’s space to use that and get the cistern against the wall. As you say, I will have to assemble the loo and check the sizes. 

FreeBear

GDB2222 said:

That looks just the thing. Thanks so much for finding it. I had no idea what I was looking for or whether it even existed. 

I wonder whether there’s space to use that and get the cistern against the wall. As you say, I will have to assemble the loo and check the sizes. 

If you are fitting a close couple toilet, the coupling can project around 180mm from the wall. With a low/high level cistern, you can go to 300mm.

GDB2222

That’s good to know. It’s close coupled. But, I’ll assemble it and measure. I can also check the height of the pan outlet against the drain.