I don't cycle enough to justify getting a decent bicycle GPS, but I wanted the option to use navigation. I have been looking for options to use an old phone of mine, but I didn't like any of the off the shelf products (or the good products were for iphone/out of budget.
Found a video last week of someone who had DIY'd a mount and I liked it, so below is the result.
Short video
Yes, I was looking at that too but when I found this I thought it was much better (for me).
Main benefits being it's cheap (case £2, adapter £4, mounting arm £3), and easy to adapt if I decide to use a different phone.