I'd definitely recommend complaining! So far, I've never met a cycle route that was impassable to my trike - I've found a few that were too steep or stony for my current fitness level, but none have been too narrow or dangerously potholey - even though some of the roads round here are a bit unpleasant.

I would recommend that you complain to Reading Council's Road Safety Team and cc it to the Reading Cycle Campaign. Even if you're not already a member of the organisation, they should be interested to hear from you as it involves their local area. You could even cc it to the Tricycle Association, although my contact with them so far has been a bit disappointing - I was hoping they were more of a campaigning organisation than they seem to be and that they'd have lots of people who could help with the whole "allowing of tricycles onto trains" thing. In fact, every single one of their events requires a car to get to, and they seem very focused on racing, which isn't something I'd ever enjoy. I'll see how it goes, anyway.