The handbook says remove the plastic cage around the filter and wash out the material and re oil.On my bike the filter is glued to the frame which makes it trickier to clean and re oil.Anyone else found the same problem?Surely I don't have to remove the filter material and re-glue it?

I use an old roasting dish, just place the filter flat in the dish with the cleaner and squash the filter flat with the palm of your hand.

When it's clean leave it upright to dry, then re-oil. Oiling can be a bit of a problem if you use moto-x oil, but less if you use a spray oil like K&N. It's easy to put too much in it as you can't wring it out like a full foam filter. I normally have a small ammount of blue oil running out of my bike when it's upright, but better too much than too little.