The next thing that will happen is that the case is transferred to your local county court. You will receive an order from the court once the allocation judge has reviewed the case. At that point the judge will either strike the claim out, order the claimant to send further detailed PoC and then give you another opportunity to amend your defence or will simply assign a hearing date. If neither of the first two things happen, then the claimant will have until approximately a month before the hearing date to pay the hearing fee. It is at this point that they will discontinue.
Depending on how busy and backlogged your local county court is, will depend on when this will eventually be over.