I think maybe with the recent postage increases, retailers just aren't willing to shoulder the cost of postage anymore... it was probably doable when a packet could be sent for a pound odd, but a small packet is now up to well over £2 just on postage, let alone the packing.
On your second question yes, many of the top end Gillette cartridges (Fusion and Mach 3 certainly) are made at St Petersburg Products. Some of the cheaper cartridges are made in India, I know the Gillette Guard and Gillette Vector are. Makes sense seeing as their main market is in the region.