It is becoming increasingly difficult to get into any university without having GCSE maths and English at grade c or above. Colleges know that it is fairly pointless accepting students without GCSEs onto Access courses, because they are unlikely to get any offers from universities.
It is possible to do the GCSEs alongside Access at some colleges, but it entails a huge workload, and I definitely would not recommend it if you have any other commitments (children, part-time job etc). You are more likely to succeed if you do the GCSEs this year, and Access next year.