Libbi is beautiful!! She looks a little like my Mum's old Arab - who was a typical nutcase, so I'm sure you're glad Libbi is controllable, at least most of the time
lol. I'd say your Riding is brilliant!! I like how - unlike most Riders - you don't tend to saw at Horse's mouth to get the Horse on the bit, and when She's doing as She's told you take the leg off immediately, like I do as a reward; which shows as She's obviously enjoying Her work
It's a pet hate of mine when Riders are inconsiderate and focus so much on getting the Horse into 'an outline' that they forget about the Horse themselves.
Something you do do though - which I am *definitely* guilty of
- is that you tend to watch Libbi a lot and as you came to the corner closest to the Camera/ Poles at this end of the arena you tended to lose direction ever so slightly; though I find myself unable to do a straight line at times when I'm concentrating on my Horse too much too so as I said, I can't really advise on how to stop it other than to try to look up and around you a little more
But something that I did notice is that as you make the transition into canter you immediately tense up - as if you're expecting Her to shoot off or something. I'm fortunate in that I don't tend to go stiff and tense when Riding - though that's probably because I do a lot of bareback work and any bad behaviour doesn't tend to bother me after working with sooo many problem Horses since I was little
You can see you tense from watching how Libbi goes - notice Her tail lifts (which is an Arabian thing I know, tends to signify She's excitable - even my baby Boy who's only 1/4 Arab does that too
), as well as Her ears coming back, followed by Her bringing Her head up and back at you which is a sign of resistance. Your position totally changes and though you tend to relax the longer you're cantering, you do tend to tip forward (only because you're tense) which causes your stirrups to slide back, consequently allowing you less control of your lower leg movement. Perhaps get your Instructor, or even your Mum or a Friend, to lunge you on Libbi so that it isn't your concern how fast She's going since She won't be able to evade control, but maybe it'd help you relax into your seat more by practicing some non-stirrup work and maybe practice stretching yourself more so that as you're cantering you're sitting deeper into the Saddle. This naturally encourages a more relaxed position - and because Libbi is so responsive it'd help to prevent that rush rush rush mentality that tends to overcome Horses as the Rider tips even ever so slightly forward
Sometimes I've got to really gee my Horse up to get Him into an active trot let alone keep His canter going - but I have trained Him to be extra responsive to voice commands meaning I don't have to move a lot whilst Riding Him - has pretty much made me unfit to Ride a lot of Horses atm though, which I'm going to have to remedy before my stage 2 Exam, oops
- but it's meant I tend to have more control over Him without having to change my position a lot
I do find a lot of ground work helps achieve this, and as you say Libbi is fab to handle on the ground then perhaps it'd be beneficial to work on controlling the canter in hand before trying to attempt improving Her canter whilst Ridden??
The Spanish Riding School start all their Horses off with groundwork ya know
Of course I don't actually know you or Libbi so what I've said may actually be waay off the mark, but hopefully you'll be able to find a method of training that works for both of you
Anyways, all the best - you should be sooo proud to own such a gorgeous Horse, and for Her to be so well behaved for an Arab, you've found a real gem there!! I'm sure She'll calm down eventually anyway, Good Luck!!