No.
BCUK's policy is not to change a username unless there's a valid reason (privacy, dodgy username, etc.) - postcount is a keyfactor, as per definition cunfusion submerges after a name change. A username is your online identity, therefor it should be chosen wisely when signing up. If you don't, you simply have to live with it, simples. Creating a second username (new account) will earn a permanent ban
In the past we had dedicated Mods for subfora (a Mod for Kit Chatter, one for Edged Tools, another for Bushcraft Chatter, etc.), it didn't work out as Mods have a life outside the forum. Some can't access the forum on a daily basis, so work that had to be done in those sections was left undone. Same eventually goes for a dedicated Mod for changing usernames (which ATM is something only Admin can do). And you don't want to do the same thing over and over, as it gets dull.
Once a month I go through Kit Chatter & Bushcraft Chatter and move all threads that are posted in the wrong section ... On average I move between 75-100 threads a month, simply because people don't read or think and simply bung on a thread ... Moving threads is boring ... very boring ...
Though I like the idea of donating a fiver to charity for a change of a username - as charity is something we encourage. As an Admin I'm here to keep up the website, to advice the Boss which direction we have to go with the forum and how to make it pay for itself (a forum does cost money: server costs, software updates, etc). By giving members the option to change their username if they donate to charity, we basically undercut ourselves. Forum resources are used to generate money, but not for the forum.
We're not against charity on BCUK, though we don't want the forum to be flooded with all sorts of charity thingies running at the same time. This is still a bushcraft website, not charity ...
Having one dedicated charity a year might also influence members individual endeavors (think the Jojo's daughter bike ride, Mrs. MagiKelly marathon, etc.). I think supporting endeavors, run by our own members, would be more appealing as these members are one of us.
Now, technically this thread turned from a discussion thread about usernames / charity into 'give to CHAS' thread. To run such a thread you need the OK from the Boss, though he'll be back in the New Year. It's Tony's forum, so he likes to know what's done and which charities are chosen. If he doesn't like it, you wont get permission.
Since he isn't available and CHAS is a charity that has to do with children, and he likes kids, I'll give you the OK to run it. But try not to come across as if you're pushing it (and don't let it run for too long). I know you are enthousiastic about this cause and simply trying to stir folks natural philanthropism - which is cool.
HTH
