First question, where will you sail her?
The 1m yachts can be 1/2m or more deep at the keel. If you don't have a jetty to launch from you have a problem. If you have shallow launch area, same problem.
What are other people near you sailing? Is there a club?
These people can give a wealth of advice that will save you a lot of time and money. Also, if you buy the same class of boat as them, you can sail with them in fun, or serious, racing. There is also a chance to buy spares if they upgrade.
1m yachts are usually 1.8-2m tall when rigged. You need to find a model that is designed to be de-rigged quickly and easily, not always the case. If you are travelling around a lot and just want to pop a boat in local waters a 1m yacht may limit your options a lot.
Smaller yachts like the Graupner Micromagic, and the Victoria will go into a car rigged, and are still big enough to sail well.
The Victoria will sail in 9" of water. Build log here
http://www.modelboatmayhem.co.uk/forum/index.php?topic=4231.0Not sure about Micromagic (hopefully someone else will chip in). Someone else mentioned Nirvana as a good RTR, I could not find these in the UK a while back.
If you are on a budget, then consider this smaller class.
Look at the total cost, some boats are ARTR (Almost ready to run) but these may still need a radio and sail servo. Others are RTR and come with the radio and sail servo. Just check that they have a hobby grade (not toy grade) radio if they are 27MHz. Or you can get a cheap 2.4GHz for under 20 pounds.
Is there weed in the lakes where you plan to sail? If so you need to consider the keel design, a model with a swept back keel will be needed.
Really your best first port of call for info is a local club. See what they are sailing, and they can also advise on suitable waters.
Do a search on here
http://www.modelboatmayhem.co.uk/forum/index.php?board=112.0 or post here and ask if anyone knows a club near a specific town, it doesn't need to give away where you live, if you are sensitive about personal data.