Yes they do accept re-sits, but you will have to include both your GCSE certificates on your UCAS application if I'm not wrong. In terms of your circumstances the only way you can include them if you want is in your personal statement or maybe in your teachers recommendation, but I'd recommend keeping it short and concise. In the end its best you contact your preferred unis for further clarification. You haven't mentioned what course you'd like to study but often universities don't really score on your GCSEs for certain courses.