rpenmanparker 

OP, you keep talking about truing despite having been quite correctly advised that a wheel can be perfectly true and still very prone to spoke breakage. There is nothing wrong or unsuitable about your rims or hubs. Your spokes may be a good model choice, but they were poorly tensioned. Now they are ruined. Get the entire rear wheel respoked by a competent wheel builder, not by an unproven LBS mechanic. Some know how to build a wheel, some don't. Find a real pro wheel builder. Lacing, tensioning and truing aren't expensive labor charges. The spokes should have tension on the drive side of about 120 kgF and all be within 5% either way of the average tension. The tension on the non-drive side will fall where it must, but it too should be uniform to +/- 5% of the average on that side.

If you can afford to have the front rebuilt at the same time, by all means do so. Front spokes see much less abuse and last longer, but I wouldn't trust your front wheel any more than you are able to rely on your rear one. Same rules for tension range except that it will be the same on both sides.