dmesg | tail gives

[  283.260285] hub 1-0:1.0: unable to enumerate USB device on port 6
[  286.648037] usb 1-6: new high speed USB device using ehci_hcd and address 7
[  308.975996] usb 1-6: configuration #1 chosen from 1 choice
[  313.976179] usb 1-6: can't set config #1, error -110

lsusb shows

Bus 001 Device 007: ID 045e:ffff Microsoft Corp.

lsusb -v gives

Bus 001 Device 007: ID 045e:ffff Microsoft Corp.
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0
  bDeviceProtocol         0
  bMaxPacketSize0        64
  idVendor           0x045e Microsoft Corp.
  idProduct          0xffff
  bcdDevice            0.00
  iManufacturer           1
  iProduct                2
  iSerial                 2
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           32
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xc0
      Self Powered
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         8 Mass Storage
      bInterfaceSubClass      6 SCSI
      bInterfaceProtocol     80 Bulk (Zip)
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0

Think I'll do a clean Ubuntu install and see if that helps. Unless you can suggest any voodoo?