Can I get insured on my friend's car temporary if I have not had a uk licence for 12 months?

Short answer is NO unfortunately. Short term car insurance is a risky business and insurers do not want to take the risk of having to pay out when they know the risk level is very high. Although at 28, you qualify for the 'being over 21' criteria, you however do not meet the second requirement of having your licence long enough (that is for at least 1 year). There are only a handful of companies which offer temporary car insurance and it's the same criteria among all of them.

If you already had comprehensive insurance cover on a car that you own, you would have been able to drive your friend's car under third party cover. Although that's not guaranteed as some insurers do not include this feature with their comprehensive policies, this is something else to think about though.