The LAPL does not expire. The experience requirement is a rolling assessment. The minimum of 1 hour training with an instructor is a total. This total is to be completed within the 24 month period before flying. There is no set date. So prior to flight you must look back to check whether you comply with each requirement. You can avoid all this by undertaking a flight with an examiner.
There is a lot that can happen between now and the end of March. All we can do is hold our breath. At the moment 'private flight' is not allowed. Expect little from the CAA on the LAPL, other national Licenses and the private grade medicals until there is a government announcement relaxing things. Now that the UK LAPL is a wholly UK licence restricted to UK airspace perhaps they may allow the use of a Medical Declaration. The same as the national PPL and the NPPL. They will have to do something with the massive backlog of Class 2 and LAPL medicals accruing. Note: the medical expiry date is the last day of the month.