What can I treat a fence panel with that isn't paint?

[iain3915]

I have a number of these types of fence panels which I want to tidy up a bit and treat but I don't want to paint them with fence paint (I'm not a fan of the painted look). What can I treat the wood with instead that will maintain a relatively natural look (and also is cheap enough to make sense to paint cheap fence panels with)?

 

[bernardgreen]

My side of the new fence my neighbour has put up will be given two applications of Sadolin Quick Drying Wood Preserver followed by one application of Sadolin Extra Durable Clear Coat.

But it will have to wait until the weather is cooler as the first attempt was so quick drying that the brush was going hard within minutes.