Ah good choice. That's my local parkrun (less than 2 mile away) Fast and flat, other than that bit of bark and sometimes some wind as you come back towards the start line it's an ideal PB course (and mine too)
Worcester half in September might be a good option for you?
Manchester is a good course, just the one very minor incline.
Newport is flatter still, but Christ it's grim down there.
I'm booked in for Chicago and Valencia later this year, although I'm not sure I'll be able to do the former now, due to life - must do Valencia though at all costs