"Yes rash is a known symptom."
Strange that the NHS don't seem to mention it.
Nor do America's CDC who show a longer list on their website: Centre for Disease Control
Watch for symptoms
People with COVID-19 have had a wide range of symptoms reported – ranging from mild symptoms to severe illness. Symptoms may appear 2-14 days after exposure to the virus. People with these symptoms may have COVID-19:

Fever or chills
Cough
Shortness of breath or difficulty breathing
Fatigue
Muscle or body aches
Headache
New loss of taste or smell
Sore throat
Congestion or runny nose
Nausea or vomiting
Diarrhea
This list does not include all possible symptoms. CDC will continue to update this list as we learn more about COVID-19.