chrisa wrote in post #16059756
Do a search for welding glass. A cheap 10 stop ND substitute.
I've tried that, and IMO, the wacky color tint is way screwy to correct. Plus, the OP is looking for a vari-nd.
I think for the 10 pounds, it's worth giving it a go. You'll either decide you love it, and want to upgrade, or that you don't use it enough to justify the cost of the upgrade. In either case, you're not out much, and you could probably resell it on eBay for 5 pounds. I've had one of those in my watch list (US ebay, $7) for over a year now. One of these days I'll pull the plug, but in the year, I have found I haven't 'needed' it, but it would have come in handy. Why have I been hesitant on the $7? Pure, unadulterated laziness. 
If you get it, let us know how it does.