I've had this for almost 18 months now.
I've been given exercises from my physio and told to call back before May if things haven't improved .... it's looking odds-on that I'll be contacting him soon to see what other options are available. I've been told a steroid injection usually helps .... but that will be my last resort.
I can't honestly see how the difference in price can be justified between off-the-shelf and bespoke insoles .... just my opinion though.
You've just reminded me though, I do need to replace my insoles as they tend to lose their support after a while.
If I remember correctly, I got my last pair from Sports Direct and I think they were Slazenger ..... I shall pop in this week and have a look :)