thanks all for the replies, yes i have seen people pricing on both ends of the scale, whenever i do a quote i always try and tell the customer of some of the littler parts or things that other plumbers / installers may not be including in their quotes. i have only had my business for around 1 1/2 years so still very early days and still getting my name out there. i think i have done well so far and managed to get some good servicing contracts. im sure as time goes by i shall become more in the know of pricing etc.
An old rule is never discuss your competitiors quote, standard of work or materials they use or leave out, if you start down that road you are using valuable time the customer has given you to explain what your standard of work is and the materials you are proposing.
Take a look at the list Whipes started, you don't have to go into a crazy amount of detail or show the size of every radiator just acknowledge you are fitting them, for example:
What Whipes said +
Supply and fit new radiators to hall, sitting room, three bedrooms, kitchen and towel rail in the bathroom C/W TRV's as discussed.
New boiler, Make model
Expansion vessel, etc, etc
You include the little details, typed up, easy to read in the order that you will carrying out the work, that makes it easier to for you to include everything and easier for the customer to follow.
When starting out I used a neat folder with the quote inside, sometimes I would include manufacturers brochures, the reason was my quote was not another envelope the customer could easily lose or get mixed up with their electricity bill, it also looked professional.
You can also find using that method you are charging for every detail, leave out a zone valve and you are down the cost, if you include it in your specification you will not be inclined to miss it when making up your quote.
When possible hand deliver your quote, that way you can go through it with the customer, always remember to thank them for the opportunity to quote and tell them you don't use pressure sales tactics to take their time to go over your quote and feel free to call you if they need anything clarified.
A hand shake can leave the door open to recommendations to others if they go with someone else who they feel didn't deliver everything you were proposing.
My advice is don't start to leave out the smaller details or use cheaper materials, that is what seperates the professional who is building a business from the one hit wonder.
Best of luck.