I've got two questions that came up when we were thinking through possible options depending on the outcome of the
11+ and St. Anselm test results of our boy.
In case he fails the 11+ but passes the St. Anselm test (but he is really dead keen on going to Calday) we would consider
an appeal to Calday. In this case we would have to put Calday first on the preference form and then St. Anselm. Then he
would automatically fail Calday based on non-qualification and could be offered a place at St. Anselm and depending on
the outcome of the appeal he could still get a place at Calday. Is my understanding correct?
If we would make no appeal or it fails and he did take a place at St. Anselm, could he still try for Calday a year later at the 12+?
Not in your area, but the answer to your first question is 'correct'. Strictly speaking, you don't have to put Calday Grange first on your CAF, but it would make things simpler if you do, because then you know that you have been turned down, have the right to appeal etc.
As to the 12+ question, does Wirral have a formal point of entry at 12+, or would you be waiting on a continuing interest list for a place to come up and a further exam to be held? The latter is how it works here (Southend / Essex grammars), but I know that at least in Buckinghamshire there is a formal 12+. (Unfortunately, in some areas schools have a rule that 11+ 'failures' cannot reapply until the 6th form entry round