hey there :)
For implementation consulting graduate roles in the UK the application windows usually open in the autumn or early winter for the following year, with deadlines often between October and January and interviews running through winter into early spring, though some firms have multiple rounds or spring deadlines too. Preparation means getting comfortable with case basics, problem structuring, business sense and communication, and brushing up on Excel and behavioural stories ahead of interviews so you can show clear thinking and impact under pressure. You can always reach out if you want specific firm timelines or how to prep.
best,
Alessa :)