I assume that for all of these i need to get a better understanding of Ruby itself but does (say) Padrino translate directly into skills i would use in Rails or is it indirect.
I am a PHP programmer but as i have used PHP frameworks which are clones of Rails i am finding it not too difficult
Padrino is based on Sinatra, which in turns is based on Rack which is also the same ruby web server interface implemented in Rails. So yes, they have some common features, but no, learning Sinatra won't help you much in learning Rails if you don't learn Ruby before.
If you have used web frameworks before you are already familiar with MVC, templates and models. What you need to know now is the framework specific syntax so you need to work directly with the framework you want to learn.
Rails and Sinatra shares some common principles and habits which belongs to the Ruby ecosystem. But you would need to learn Ruby before in order to better appreciate these frameworks.
Don't assume the "learning Ruby" step to be an optional task.
This might be a more controversial opinion, and I'll admit to being new to both still, but as someone who just spent a week on Sinatra and then moved on to Rails, I would recommend going straight for Rails. Initially, it will seem like there's a lot more to learn about Rails, but if you're going to write something moderately complex, you're going to move to Rails eventually, and it's less work 'unlearning' from Rails what you need to write a Sinatra app than it is to relearn things to do it the Rails way. You save yourself the pain of having to shift gears when it turns out that your project you started in Sinatra was best done in Rails after all (which happened to me).
This does mean it's going to take a little longer to get up to speed on Rails. I recommend starting with Michael Hartl's tutorial and the official guides. However, my advice is specifically geared towards existing developers who already know how to develop web apps and are more likely to have more complex projects in mind than beginners. Someone brand new to web app design may very well appreciate the immediate gratification that building a basic Sinatra app will offer, but that doesn't seem to be you.
Experienced developers will probably argue that you can definitely write 'moderately complex' apps in Sinatra too, and they will be right. I think Sinatra's strengths are in being a fallback for experienced developers who want to knock out a quick app without Rails 'overhead', and not as an introduction to Ruby/Rails based web app development.
You can't skip the step to learn ruby, because every ruby MVC extend it and If you have to do some important customization/optimization you'll do it in ruby.
My advice is to learn a ruby base (variables, blocks, modules, hashes,..), use Rails in real world, learn Rack and then choose the best "pieces" of the Ruby World that suit to your needs.
If you want to learn rails a good way is to follow the road map that is mapped out on this blog post. It is what I used and it was a great start. Obviously if you already know PHP there are steps that you can most likely skip, but overall it is a really good approach to taking little steps towards learning rails http://techiferous.com/2010/07/roadmap-for-learning-rails/