Hi Cardiff, I work for an external render manufacturer and I'm happy to give you any advice you need. Have a look at our website:
http://www.k-rend.co.uk/products.aspx
We make both cement and lime based render products in a range of colours and finishes. The most important factor in choosing a finish is the substrate that it will be applied onto. If your property has lime mortar joints then you should use a hydraulic lime render over them. If you use a cement render over a lime mortar jointed house it will crack and eventually fail.
If your house has cement mortar joints then you can put a cement render over them. There are a few textures from scraped texture (sandpaper type texture, flat render), roughcast or wet dash (looks lumpy on the wall), dry dash or tyrolean effect (stippled). These products are through coloured and don't require painting.
If you can remove the existing render then it will save you money, however this can take longer than you would expect. A plasterer will want you to arrange access and you should budget for around £35 per sqm supplied and fitted.
We have a list of recommended installers if you want me to send you that. Any questions let me know.
