Michelle
If you are only receiving Contribution Based ESA in the SG then the standard rate is £109.65 (Personal Allowance £73.10 SG Component £36.55) so you must also be receiving a Transitional Payment of £8.85.
To receive more you must be eligible for Income Related ESA, ESA(IR) is dependant on your household income, your savings and assets, and any hours that your partner works. See
Asset and savings rule for ESA(IR) 24 hour work rule for ESA(IR) You would then receive the Enhanced Disability Premium (£15.90) but lose the £8.85.
If you believe that you are eligible for ESA(IR) then you should contact the DWP about this, they will need your to complete an ESA3 form about your financial situation, this is not a reassessment of your eligibility for ESA. The EDP should be backdated to when you were placed in the SG.
Gordon