Rent Guarantee insurance from agent?

Hi
First time landlord here.
My agents have found suitable tenants for my 1 bed flat and on top of their 10% monthly fee and processing initial charge of £199, they suggest that I take out their Rent guarantee insurance which covers the credit checks and guarantee upto 5 months rent if the tenant defaults which includes legal. The insurance is £200. The other option is to pay just £50 for the credit checks n referencing.

Is it worth taking out the £200 insurance n checks?

Thanks