Make a list of anything that needs to be done before they inspect you and prioritise. If you do not get everything done don't worry.
When I had my inspection before being registered I didn't have my stair gates up but it did not matter cos as long as you can tell them the things you will do before minding children you will be ok, as long as all of the important things are done eg smoke detectors etc.
Do you want to postpone it? They are usually pretty understanding at OFSTED. Well they are at my local office anyway. If you do go ahead... feelingold is right, just get the important things done and let them know that you have tought about the other things and that they will be done before youget any mindees! Good Luck!!
Here are a few things I can think of off the top of my head - you will be fine, I can tell
Your passport/driving license/car insurance (get your car insurance to have business use if you havent got it already)
Fire extinguisher and blanket in kitchen
Smoke alarms (carbon monoxide detectors are good too)
Corner protectors/cushions for sharp furniture edges
Loose wires safely hidden
Safety catches on drawers/cupboards
First aid kit
A basic room by room recorded risk assessment
Safety covering on glass
Have or say that you will have a daily attendance register and individual contracts
Have or say that you will have forms for recording accidents/sickness/medication
Have or say that you will have a form for parents/carers to record everything including current development and important personal details about their child prior to them being in your care
Some books, toys and colourful posters etc that show people of all races/cultures and abilities (dont worry about having a full range of toys etc as long as you can say what sort of things you intend to get and mention toy libraries etc)
High hook to hang front door keys on
Kitchen towel holder and covered waste bin in bathroom for hygienic hand washing
Fridge and room thermometers
peckarollover... you'll be fine. The registration inspection is not like the inspection you get later on, once you are up and running, it's far more to do with checking out your home... so try and have as many safety features installed as possible. Also think about things like Fire Escape Plan (do a diagram showing routes).
You don't need all your policys done for this initial inspection, though having most of them done does help.
Good luck with the registration inspection and the wedding