You can buy torch brackets from China for around £2 posted I've got one on both my bikes and work really well,I've had them for a few years so forget the seller but I'm sure there still out there 
I have several of those, plastic, with straps, with turning pivots etc. and have only had one fail so far, but the fenix one is significantly more heavy duty and good for heavier torches, over rough ground. It is also nicely adjustable.
I got mine for about $12 a while back and had to get another one at this price.
The price is $8.79 not Pounds, so the difference in price is not huge, considering the overall construction.