Oil weeping between head and block

[Brendanmck]

Hi all . I’m currently changing the belts on the front of engine when I noticed small amount of oil has been gathering on top of the air con compressor so after cleaning it up and further investigation I’ve discovered the source of the oil seems to be weeping from between the head and the block just ahead of the first port of the exhaust manifold. Is this cause for concern or is this the result of the car not being driven very often.any thoughts much appreciated.
Thanks.