Seemingly reasonably priced for the UK - Mellanox SX6018 18x QSFP 56G FDR Managed Switch | eBay
They also have a SX6036for £388 but only one. - Mellanox SX6036 - 36xQSFP FDR InfiniBand Switch | eBay
They also have a SX6036for £388 but only one. - Mellanox SX6036 - 36xQSFP FDR InfiniBand Switch | eBay