€20 for honing including postage is a good rate for someone you can trust, in my opinion. At the end of the day, Floid has had bad experiences with members honing on another forum. I can personally vouch for Fergiebilly's honing skills having had all of my razors (x5 razors) honed by him at one point or another. All have extremely keen edges throughout the blade and are very capable shavers. That is to say, there's proof in the pudding - I've had good experiences with those recommended, and those who aren't recommended are likely to not get my time or money. Similarly, I've heard no bad reports of a razor honed by Billy. I think the fact everyone has, so far, recommended Billy for honing speaks volumes for those situated in the UK. I believe there is another who's particularly proficient with kamisori-type razors but I've had no need to hone one.
In short, it's not about proving or disproving someone, as there's a large number of variables to take into account. E.g. what makes someone 'professional'? As far as I'm concerned, Billy charges a decent rate for a good service with a great outcome, more than meeting the expectation for someone wanting a shave-ready straight. In my eyes, he's as professional as (if not more than) someone who runs a website or eBay listing for such a service. Furthermore, there are reports of companies who sell and hone straights doing a sub-par job in getting them truly shave-ready.
In the UK, Billy for sure. Elsewhere, your mileage may vary - I'd imagine going for a reputed name such as Ralf Aust is good for the money in Germany.
