They have up to 6 years to raise a claim.
There isn't any reasonable reason for them to take that long, but they could.
They have 6 years from the date of the alleged contravention to initiate a court claim. After 6 years they can still chase you ad infinatum. They just can’t sue you for the alleged debt.
They have 6 years to raise a court claim, so 6 weeks is irrelevant.