I can't give specific suggestions but can offer a couple of comments:
Cross forks (like the Winwood) are all made for 700C wheels. Your disc brakes make brake compatibility a non-issue but the bike's geometry will change quite a bit.
Generally, Aluminum forks are frowned upon. Early versions had a well established reputation for breaking and the material has gone out of favor for rigid/road forks. Steel and Carbon are both excellent choices if made by a good manufacturer. For road forks, Carbon is the current material of choice but your 26" wheels do reduce the choices a lot.
Perhaps, going back to your original builder for a more suitable fork is the wisest move.