I heard dulux extreme or diamond are difficult to work with

I have to agree with GMT Construction. Dulux is a brilliant brand and definitely the choice of professionals. Having worked with the Dulux Endurance range it can be a little thick which might be why you have heard that it is difficult to work with but you can water it down a little to make it easier to work with and use with a roller. It is a very hard wearing and wipeable making it idea for a family household. ADDITION- To water down, literally add a small quantity of water to the paint and mix well. Add a little at a time until you reach the desired consistency. Some times you can do this in the original paint pot but mostly its better to do it in a larger container like a clean bucket. Hope that helps. Hope this helps.

Dulux is a great paint,I would say professionals choice,I think by choosing it you`ll never regret it.The Dulux Diamond Sterishield Matt,the one I am assuming you speak about,is a quick drying, water-based coating containing an in-film bactericide which inhibits bacteria. It is a tough, washable, durable, stain resistant matt emulsion and is suitable for all normal interior wall and ceiling surfaces.So yes,it might be hard working with it,but if you want a good quality and a ease of maintenance you should definitely use it,even if a tradesman does the job,or you think that you are able to handle it in a safe and professional way!Hope my advice would be helpful for you.

Personally I would never recommend you dilute emulsion to make it easier to apply. The only time you should ever dilute emulsion would be to use as "misting" coat on bare new plaster. the reason being, new plaster is highly absorbent and will absorb the water in full bodied emulsion too quickly leaving the actual material patchy and blotchy. a watered down mist coat is intended to deliberately allow this to happen making the plaster less absorbent and less likely to do the same when applying the finish coats. so if, when you strip away the paper you find the walls are bare plaster underneath, then yes, dilute the emulsion to a 80% emulsion to 20% water ratio for the mist coat. then 2 full bodied coats thereafter, light sanding (de nibbing) between coats and allow each coat to dry thoroughly before applying any subsequent coats. If the wall underneath the paper is previously painted, then theres no reason to dilute. just be sure to prep the surface properly and use full bodied materials as they are intended to be used. No emulsion is "harder" to use than any other with a roller if you are doing the job correctly with a decent quality roller. If in doubt, as you obviously are, hire a professional. good luck.