Check if you can remove the old bearings. I have done this with a Myson Apollo fan and it works fine thereafter. It only requires basic tools to dismantle the fan, extract the old bearings, find the number on the bearings, search for Simply Bearings.co.uk and locate the right ones. I bought 2 sets for £8 - bargain deal when a replacement fan unit is almost £200.
Colin, August 2013