Ryanair are subject to the same rules, regulations and inspections as any Irish carrier and also are subject to SAFA inspections, the same as any other carrier.
This statement tells me you are not a pilot. This is the spin that Ryanair excrete ad nauseum to the media. It is utterly false.
Airlines are self regulating. They submit an Operations Manual outlining their own rules and regulations for approval by the relevant authority and when approved they ( are supposed to) operate accordingly. The airlines have different Operations Manuals and as such operate to different rules. Obviously there will be many similarities ( mainly to stay within manafacturer and JAR regs ) but your statement is deliberately misleading.
There are a tiny number of audits carried out by the IAA. It is not unknown for an IAA audit to consist of an IAA officer flying as the Captain of a line flight with only a Ryanair co-pilot in the cockpit. This system is completely insane. The flaws are many but it is worth pointing out the conflict of interests where the IAA officer is effectively completely responsible for the operation he is supposed to be impartially auditing. It is also worth pointing out that this does not happen with other carriers.