@Davidh - I also have a CTEK and have recently been having a very similar conversation with
@Dellmassive who has been extremely helpful. I'm going to go with the same 160W panel, but plan to use a Victronic MPPT (Probably the 75/15 as that's plenty sufficient). It also has the benefit of significantly better monitoring... I'll then just leave the CTEK looking after the B-2-B.
When I was researching, I found that there was definitely someone on here that tested a panel with VOC of 23.9 and found that he was getting 23.6 at the MPPT, and therefore didn't want to risk the CTEK. I also therefore wouldn't risk the CTEK as they can apparently get fried when above the recommended VOC. This other chap was really reluctant to get a different MPPT, due to the lack of space under seats... but in the end also managed to fit in a Victronic (as they're pretty small!)
Hope that helps!