Changes from Casper's comments - attempt 3

Wrappers/Python/cil/optimisation/utilities/StepSizeMethods.py

@@ -101,7 +101,7 @@ def __init__(self, alpha=1e6, beta=0.5, max_iterations=None, warmstart=True):
         self.alpha_orig = alpha
         if self.alpha_orig is None: # Can be removed when alpha and beta are deprecated in GD
             self.alpha_orig = 1e6 
-        self.alpha = self.alpha_orig.copy()
+        self.alpha = self.alpha_orig
         self.beta = beta 
         if self.beta is None:  # Can be removed when alpha and beta are deprecated in GD
             self.beta = 0.5