In my experience the check consists of 2 intertwining parts. One part flying skills related, showing the ability to fly a reasonable departure,cruize and ILS approach. Two, more CRM related, being able to adapt to a strange environment while working as a professional team.
For the first part: If you fly manually on a reasonably regular interval (even on an airbus) you should be more than OK. If you flew a turboprop you should have ample handling skills to pass the ride.
I recommend just installing a flight simulator on your computer and getting hold of a joystick and watching the needles spin around in a holding pattern or SID. Couple that with some raw data ILS approaches on line in a 'real environment' and you will be more than adequately prepared. Don't feel the need to splash out money for an expensive sim, you can do it for real on line anyway. In my experience there is really little difference, flying an airbus raw data is challenging enough. Moreover, the sim is not hard to fly, it is actually incredibly stable, especially on an ILS.
For the second part : The environment is such that everything is strange to you. I think this has a purpose,seeing how well you adapt to for instance : an old BAC-111 sim, Aerad approach charts (BA uses these), unfamiliar checklists, a separate minima sheet, no real SOP's, raw data flying. All these things are non-events, but combined, these factors won't make you feel the "at ease" pilot that you are on a daily basis. It's a matter of taking time and care when working in this new environment relying on your professional background to guide you through.
In general, the sim can be summed up as follows :
SID
Cruize (some aviation related math questions)
Preparation for non precision (but wx degradation/operational/technical issue causes diversion)
Vectors or procedural ILS to land.
Good luck