I've broken 3 spokes so far on this wheel so I was wondering if there was third party wheel manufacturer that made a more robust wheel and that I could "drop" in the hub gear.
Or would it be worth getting a bike shop to remake this wheel using good quality spokes? Where would you recommend.
Spoke breakage is usually due to a poor build (rather than poor components necessarily) and under-tensioned spokes is usually the culprit. Stock wheels on bikes, even bikes costing well over £500, are notorious for that. The build of the wheels, especially the rear wheel, that came with my brand new Cadenza a few years ago was terrible.
If I were you I would seek out a good bike shop nearby to get it rebuilt, certainly replacing all spokes, and rim only if necessary. If you post a question in Bikes and Accessories within the Technical session giving your location someone might be able to recommend a good local shop.