is there a insurance deposit scheme

I have 4 french students renting from Sept for 12 mth - my rent now falls into the DPS to save them t/f money bank charges and currency flatulation is there an insurance type approved scheme you recommend for that method I take 2 month deposit to avoid the summer if they leave early .

I see you have advised that unless there is a uk Guarantor there's not much chance in getting any money back in case of a problem - what do you recommend .

finally one of the parents wants to pay all the the rent monthly - dose this affect who am dealing with the students will all sign the AST .

Thanks you .