Well, I have the answer to some - and need a tradesman to tell me the answers to others !
1. It's the outside wall to my house - the outside of it is made from bricks, the inside has a smooth surface (plaster ?)
2. I have no idea if there are any pipes etc behind it - I was not there when it was built. There are no light fittings or sockets etc etc below or around the area I need the bracket however, and no external wires. There ARE two large immersion heaters c. 6 ft. away
3. I am looking into buying the bracket - just need the mortgage company to confirm they'll approve the remortgage in order to free the funds to get it. I'll have it in a week or so
4. The fixings etc etc will all be bought with the bracket.
I'm not a tradesman but I am the daughter of an electrician and the niece of a carpenter who - between the two of them - know a bit about plumbing ... there is a gadget you can get from Homebase/B&Q/anywhere similar which you can use to see whether there are pipes or wires under the surface of a wall - I reckon EVERY home should have one of these, even just for the purposes of hanging pictures: you would be amazed where workmen will run pipes and cables (especially in flats and conversions) and such a device will save you lots of time and money in the long run. Possibly your life, too.
Your smooth surface may be "dry lining", in which case you will need a particular, special type of fixing because walls constructed in this way aren't solid and so don't have anything to grip the fixing - your mortgage survey should tell you what kind of internal walls you've got and whether this is an issue. If they are dry lined, let me know and I will tell you the fixing you need (can't recall the name at the moment but can check my toolbox and come back to you).