Hiya Bigpie,
Think annual subs is something daft like £5-£10, but don't hold me to that. With the Skill for Life you get the first year chucked in, so get all the IAM offers, discounts and membership included, so not had to pay anything extra yet. Once you pass the Skill for Life then you get the green badge, matching sticker for your bike and become a full member. Completely optional if you want to keep up with the IAM subs after 12months. So at the moment its only £69 instead of the full £139 for riders in South Yorkshire.
With the Rotherham lot then its usually customary to pay for your instructors lunch, never been asked about contributing for their petrol, and if there is a couple of you out with an instructor you usually just take it in turns to pay. So some weekends nothing to pay apart from your own petrol and grub.
Both Sheffield and Rotherham groups go out every Saturday, with optional ride-outs in the week once the nights get lighter. But up-to-you when you can actually make it, no set targets, you pretty much have 12months to pass. Mine's been a bit stop/start with working events on weekends, so the instructors are used to it and usually set you some homework or things to practice on. Getting down to the nitty gritty with my instructor, so hopefully a practice assessment in next few weeks.
You can just nip down to their meets on Saturday mornings for a chat or they will even take you out for free on a half-hour assessment and talk through your riding and what they can help with. When you can fit it in with everything else mate then just drop us a PM and more than happy to meet up and introduce you to the Rotherham lot.