It is pretty simple to get at once the glove box is out of the way to give you more light/access. Only 4 screws to remove that.
Best not to get a silly cheap one as there has been a lot catch fire!
For the Corsa D it was under £20 from main dealer. Buy from a trusted seller with good feed back or a trusted business. Autovaux, Nevlock, LMF Vauxhall super store (main dealer with old/new stock clearance)