Hi Daz
I would say that your best bet is to go into shops and try on everything. With climbing shoes, if you are starting out go with what is comfortable. Dont worry about technical shoes or amazing types of rubber as you are going to trash them within 6 months anyway. If the shop assistant tells you that you need to buy a pair that is a size too small slap him and go to another shop. This used to be the case years ago coz shoes werent made very well but today most will be tight enough at the right size.
As far as harnesses go I go with the same kind of questions that the turbo sloth posted. Again if you are starting out get a harness that you can wear with shorts or winter kit. Get one with nice padding and a good amount of gear loops. Any shop worth its salt will have somewhere that you can clip into and hang in the harness. You wont know if its comfy unless you do this. The same goes for shoes, shops should have climbing holds or an edge to stand on to see if the shoes are good whenthey are being used.
Last thing dont worry too much about price if you are climbing low grade or new to the sport. Alot of the time you are paying for a brand name or a technical shoe. Dont forget to take your socks off before trying them on or they will be too big when you come to climb.
Happy hunting