Getting in to a band will be great for you Rich, pleased to hear it.
A few years back I regularly gigged a 100 watt combo. Mostly it could be heard but didn't really possess enough headroom to do it in a pleasing fashion. It all sounded a bit flubby (tech term) and like it was going to give up and expire. Things may have been better if an extension cab could have been added but with this particular combo, it wasn't possible.
If a second cab could be added to the Roland, then maybe it would be enough for you. It will depend on a number of factors of course, not least the drummer.
If a cab can be added to your Roland, you could borrow one of my Mark Bass Cabs and see how it sounds and whether it's loud enough.
Don't know much about Ashdown kit but I'm sure there are plenty on here who do.