Yep, all understood -- re the initial call though, often have found that the slightly longer initial call isn't always appreciated if freq is busy, whereas with other units (maybe Solent?) it can get a better approach. Opted not to stay with Farnboro' or ask him to coordinate as he was clearly WAY too busy (yet very obliging!) already
I think an issue with Solent might be as you say that non-transiting a/c call them too much... its an area of instruction that is always vague for students: "you should probably call some nearby unit for FIS" is about all you get told... and I think early solo students are encouraged to call rather than not so as they are talking to someone in case they need help and the instructor feels somehow safer if this is the case, maybe?
Andy