Advice please about pitfalls when renting.

Despite my user name I am not quite loaded enough to buy a property, or at least I would rather rent somewhere and watch the housing market for a while.

My main three concerns when renting are: 1) What steps (apart from returning the property and inventory in good condition and getting a written receipt for my deposit) can I take to ensure that my deposit is returned to me at the end of the contract. Also some letting agents show properties for rent as "property bonded". I assume this means that the deposit required is greater than the usual month or so?

2) How can I check that the letting agents are reputable and therefore won't go out of business or not correctly pass on my payments to the landlord/lady.

3)Being very paranoid, are/should the letting agent be required to demonstrate that they are indeed authorised to let the property by its rightful owner.

I have some general concerns mainly because I am going to rent somewhere in the £1000-£1250/month price range. Also I have noticed that compared to 3 or 4 years ago there are many more letting agents around, many of these look quite small time operations which makes me a bit more nervous about parting with 2 to 3 grand up front..

I realise that some of you on this section of the forum may be landlords/ladies rather than renters but all advice on the above and any other issues I should consider would be greatly appreciated.

Thanks.