This time last year we decided to have our outdoor pool filled in with extended patio to some 80 sq/mtrs, I contacted bricklayers and groundworker, lots of interest lots of visits to quote. 2 major problems, 50% never quoted as they could not use a dump truck and digger, those that did quote found it impossible to caculate the crushed concrete required for a kidney shape pool even though I told them it contained 9500 gallons. Infill quantity varied by 200% and so did the quotes which could not have been the infill as crushed concrete in a 30 ton load is only £230. By Easter I almost gave up but tried again this time with Rated people and a several garden designers quoted, the guy that did the job was a garden designer lived 5 miles away and I knew his Father, I had worked out the tonnage of material required and was begining to think I had got it wrong but we were very close. He and his team barrowed 90 tons of materials around the house did a brilliant job in August the driest period last year.
The moral of this story is to allow several months to find out those actually capable of doing your job and price will not alway produce the best workmanship.
PS
Anyone thinking of a pool this summer I have all the ( very expensive) equipment you will require for daft money.