Looks like tube currents , but after over 2 hours they will be gone especially with an open ended tube like yours , so I would say its 'seeing' eg. atmospheric refraction .
I had the same sort of problems last Saturday night up here in Darwin with my Takahashi M210 , it looked like out of collimation? , then tube currents , then the seeing , David , it was horrible ! , I was only able to get to 150x max , when normally 300x on doubles is easy with my Tak and it holds collimation very well .
Oh yes a star test was out of the question , the 'Seeing ' was so bad last Saturday .
I would bet its the seeing so don't worry .
Brian.