Purchasing and using this box spanner is the difference between a cack-handed, frustrating job and one that just sails through. Guess how I found out the difference?
The spanner itself is very solid and quite long enough (the picture does not really put it into any kind of scale, it's bigger than you might expect). It fitted perfectly on the backnuts of the taps I just installed (obviously you can't have existing fixed pipework in the way, but with the flexible tap connectors in use today that was no problem).
Only ommision was a cross bar but I used an old, solid screwdriver and it did the job well. One should have been suppliled though, I feel.
A plumber would have one of these spanners in his toolkit anyway, but if you're a serious DIYer then you should too. Not worth the price? Well good luck with using standard spanners under a basin - and how much would it cost you to call out a plumber to do the job?
In my book worth every penny and I now have it for life.