If you're in a SWALEC area have a look at Orbit Energy. I was saving over £160 on dual fuel, then they upped their prices a few days before all others. But now they have an even cheaper tariff.
https://orbitenergy.co.uk/
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elec SC: 23.593 p/day 11.399 p/kWh
gas SC 25.2340 p/day 2.431 p/kWh