But that is exactly the issue Webby.
Most people take their car to a garage and expect it to be worked on by people who know what they are doing (you could use words like experienced, trained, expert, done it many times). After all, especially at Main dealers you certainly pay enough - £80 ph.?
I class myself as someone who "if others can do it then so can I " and I did my own Omega having researched it and got the locking tool, DVD and big pulley spanner. True it was a bit daunting but having done one , I would do it again and much quicker.
I have a lot of respect for you and other folk learning the trade but it has to be in an environment where someone has previous experience. Over here in Spain, I asked around a lot before trusting my Peugeot diesel engine to a garage to have the cambelt changed as it is our only vehicle and I needed it back same day. I have been bitten before by garages saying one day and then saying got wrong part, ran into difficulties come back in two days time etc. One took a week to change an oil cooler.