Hey Graham,
I apologize, my friend! I just checked your profile AFTER I posted about this thread. Tractor Supply might be a bit of a ride for you, LOL!! Surely you must mow grass in the UK, and have lawn mower repair shops? We have a farm supply store chain in my area called Tractor Supply, and over the years I have solved many problems with my Ventures by shopping there, and thinking "Outside The Box" so to speak. I am sure you have a store similar to this in the UK. One more thing Graham, After you have added the filter, if the filter hangs too close to the ground, cut off some of the overflow line to return the end of the filter to it's original position.
Again, I apologize for not paying closer attention to your location. But rest assured, the fix is sound advice!
Earl