laying the field at 1.8 etc

Yes, tried it over about 40 races , at various odds.

You will get 2 matched often, 3 sometimes , and one race i had 4 matched below 1.40 . Overall though i finished level or slightly down, as there are so many races when a horse is going well 2 furlongs out, hits the front shortly after , and wins comfortably, and then you are only matched on one.

So it doesn't work . Unless you are able to filter the races so that you are getting on when it's more likely to be a blanket finish, so you have to consider the race distance, certain track/going combinations which maybe lead to more in running errors and maybe also bet when the market has several horses closely matched.