Hi Katie, my speeds have improved slightly, but at peak times (evening) it's still very slow, around 100mbps download although it varies. At non peak times the speed is fine. Due to this it's unlikely to be related to modem mode.
These are my TBB graphs for Saturday and Sunday:


Sunday seems to be particularly bad, and just looking at most days, mostly between 6-11pm (and especially between 8-9pm) it's very messy, which is basically peak time.
Hope this can be resolved, I've pretty much always had great speeds in the past so it's a bit puzzling. I really want to upgrade to Gig1 when it comes here too but if I can't even get my 350 then not much point 😕 thanks for your help.