It is very important to understand the training pathway and training application timeline. Obgyn Training is 7 years in UK (ST1,ST2—-ST7).ST means specialty training. You can apply from ST1 or ST3 level for Obgyn Training. If you want to do trust grade post/Non training post you can apply without being worries about ST 1,2,3,4, levels. Because when you apply as non training or trust grade you are just titles as junior clinical doctor/SHO/FY2/3/Junior registrar/Senior registrar/middle grade/SAS etc not like ST1 ,ST2 etc.
So here we will talk about specialty training as obgyn in UK. We have two levels where we can apply , ST1 or ST3. ST1 is the start of training like junior most level. You apply for training pathway via oriel (As described in other posts). You have to fulfill eligibility criteria for ST1 level if you want to start as ST1. The most important thing is you should not have more than 24 months experience in Obgyn (excluding housejob/foundation year). If you have more than 24 months in Obgyn you will qualify for ST3 directly.
CREST form / other methods to prove your eligibility of foundation years is required.
MRCOG 1 is not the criteria for ST1 but for ST3.
Teachings, Audit, QIP are important to score in application for ST1 but without them you still can apply for application.
There is no application for ST2 , ST4 or above . Just ST1 or ST3. So you need to see criteria from Oriel or RCOG site.
If you have less than 24 months experience in Obgyn you have better chance to secure position at ST1 level as compare to ST3 level. Because ST1 has more seats as compare to ST3 level ( ST1 seats 200-300 but ST3 10-50). There are many things you need to provide in ST3 application Audits, Publications, research, teachings, Audits etc, It is not just about how skillful you are in Obgyn.
That is why I prefer to start from ST1 level rather than higher level.
I hope this was helpful , please do not hesitate to contact if still confused!