Thanks for getting back to me Neurotic fish.
Please can you take a quick look at the screenshot and let me know if I'm in the correct place, I'm getting this message 'Submissions are beyond limit. Please try later.'? Do I need to deposit bitcoin to use the transaction accelerator?

I've looked at 'Quickseller' but not registered as it'll just be like opening another can of worms and already I've worms coming out of my ears : )
The screenshot is OK. That message means that they are full for now. I've got the same message.
Quickseller has a lot of negative feedback, but many tell that PM-ing him can solve your problem for a fee.
Just I don't know his fees and I cannot vouch for it either...