Stiff Gear Change New Shape Fiesta

A couple of months ago I came onto the site, and brought this topic up, I thought it was my crappy driving, after a few suggestions from members, but as it turned out it was not. I have always found the gear box on my 2009 fiesta a bit notchy, the gear change can be smooth when the engine is cold, but when the engine is very hot the gear change goes stiff, almost as if when changing gear up and down it catches slightly before going into gear, I have been on various sites, and one site overclockers were discussing this problem, it seems that the gear linkage arm with the splines on, into the gear box, can distort when faulty with the heat of the engine. They gave various fixes from replacing the part to just cleaning it. With this information, bearing in mind that the information was for the previous model fiesta, I went to ford and asked them too look at it, a couple of hours later, they got back too me and said there was nothing wrong with the car, I went down and spoke to the head mechanic who said they had checked everything and coudnt fine anything wrong, I was annoyed because I had driven a couple of friends mk7 fiestas and there gear changes were smooth, the head mechanic did say too me that the mk7 fiesta had the same gear box as the previous fiesta and he kind of smirked and said with so called improvements, he was helpful, but seemed to me that they werent interested, the fault i have described is a known issue with the previuos fiesta. I feel i am better off just going to a non ford garage and taking the overclockers step by step guide which has a picture and getting them to change the arm. My fiesta has only 11800 miles on the clock and was registered 30/12/09.

Cheers

Mick