Honestly, 10k is not a big deal in pretty much any aeroplane....They used to think that if you drove over 30 MPH you'd die - but you don't. Same goes for flying "little" aeroplanes at 10,000 feet, they will all do it ok (unless they are fcuk'd). You have nothing to worry about
Landing and taking off at high altitude is another matter though, not that you'll encounter that in the uk......