Hi Andy,
As it happens, the Met Office were looking for Trainee forecasters anyway so they probably said HR will have you apply etc - as is normal. Here is some of the criteria for these roles as per Met Office website....
Required Standard of Mathematics and Physics for Trainee Forecasters
In order to be able to fully benefit from the intensive training programme provided, Trainee Forecasters will need to have ability in Mathematics and Physics to at least AS Level or equivalent and as a guideline should have some understanding of the following areas: Mathematics: Linear algebra and vector calculus Differential and integral calculus Ordinary and partial differential equations Probability theory and statistics Information and communication technology Numerical methods Physics: Fundamentals of mechanics Basic thermodynamics Wave theory/Fluid Motion/Turbulence Basics of electromagnetic radiation/electromagnetism Competence in these areas will be tested during the technical assessment.
JK