I get the headset bearings for my Specialized’s (Stumpjumper FSR Comp and Enduro Expert Carbon) from Aire Bearings on eBay:
Aire Bearings ebay
The top one is MH-P08 and the bottom one is MH-P16H8.
The thing to do is too take the bearings out, they should have the measurements marked on them. If not it’s easy to measure them for yourself and compare the measurements to ones listed for the bearings on eBay. I have used Aire Bearings for years now and the bearings are good quality, reasonably priced and their delivery is quick too. They also sell ceramic bearings for a little more but I tend to use the standard ones and replace them when they get a bit dry and notchy as they are so cheap.
In your position I would whip the forks off and drop the bearings out to double check and then order the replacements. It’s a lot cheaper than paying £70 for a new headset!
Hope this helps. 🙂
‘weav