For them to be able to do so:
1. You default on the loan payments; &
2. They take you to Court & get a County Court Judgement against you (which will specify the amount you are to pay each month or that you are to pay all the debt "forthwith"); &
3. You fail to comply with the judgement; &
4. They return to Court & get an interim charging order; &
5. A judge, at a hearing to make the interim order final agrees to do so.
Never ignore a County Court claim. Always put in a financial statement and payment offer - even if it is only �1 per month. If a "forthwith" judgement is made apply for redetermination of a variation. If the judgement is for a certain monthly sum, never miss a payment or delay it - even by 1 day. Make sure it is paid in "cleared funds", not by cheque as the creditor could fail to bank it & then claim you had not paid.
These steps will minimise (but cannot remove entirely) the risk of a charging order