Temp agency work contract

Hi, my wife from the phillipines is applying for her spouse visa. We have almost finished gathering all the supporting documents together. As I am also the sponsor , I am concerned about my work situation.

I have been working at a company through a temp agency for close to 3 months now. I was hoping to transfer from temp to perm at my workplace, but my recent request was denied. I have heard that I may be able to get a permanent contract around christmas, as long as the company is doing well.
My income is £230+ per week and I live rent free so I believe I can meet the maintenance requirements in that respect.

Do you think it is worth applying with just the contract I got from the agency? I dont want to lose the application fee and 2 months just to find out.

thanks in advance