Cpt. Clash

My US size is 15, so about a 14 UK, -- just not enough room. I end up resting either the front or back of my foot on the shift lever of the last shift that I made -- shifting up leaves my heel resting on the back lever, down my toe on the front lever. Would really like to get some more room though...

I love my 1300, but have a large foot and there is NOT enough room between the heel and toe levers for my riding boot (55). I have searched around and have not found any one else mention this issue, nor have I seen any replacements/solutions. Currently I have to make a lot of foot gyrations to shift. I'd love to keep the heel/toe style but need more room between the levers. Any ideas? Thanks in advance!