Put a photo up of your clay drain, depending on type, depends what you may be able to do with it. Newer Vitrified clay type, you may get away with cutting a hole, or these are fairly easy to swap if need be.
The older Salt Glazed drains are one big lump, may not take kindly to you trying to cut a hole in and as Ian said on the Linked post, better swapping that out for a Bottle Gulley, which has 110mm inlet on both sides, then use a channel drain adaptor to connect.