I’ve got round this problem by a) getting our hosting service to make wp-admin available; b) using the Rollback feature in WordPress to take WooCommerce back to V5.0.0 from V5.1.0.
More than a little worried that if I try to upgrade WooCommerce to 5.1.0 again it will result in the same failure
Thanks again, the customisation was in WooCommerce / Storefront and it must be aeons ago that I set it!
OK thanks for the reply, I’ll try to hunt it down!
