Yep… Go for it.
I rode it last year (in the dry). It was by far the longest ride I had completed, although I did get a couple of road 100 milers under my belt during that summer, along with a few big 8 hr mtb days out in the hills.
I am pretty certain that if you are fit enough to ride for 8 hours, then you will physically be able to keep going for another couple, for me it was just a matter of determination and stubbornness that kept me going towards the end. More of a mental challenge at that point somehow.
Having said that, I completed it and was happy to do so, but I won’t be back. It is a good event, well organised and an amazing sense of acheivement to finish, but as a days riding it was possibly one of the least enjoyable that I’ve had 🙄