The signal in scotland is excluding the upper most highlands generally 52 db on Astra 2A,B,C, just the same as the rest of the UK.
Do you have any signal obstuctions in the path?
You can also check the satdox web site - check around your local area for standard
sky dishes.?
If you wish you can also use the satmaster software (you can down load a copy) to check out the C/N Ratio with the flat plate.
The old BSB dishes also had a typical 1.1 -1.3 db lnb not the best when you are trying to recieve on a small dish! the other problem is they do not cover the Astra 28.2 east
sky digital frequency range from 10.90MHZ through 12.480MHZ.
The 54cm Flat Plate with the conditions that you have are excluding the cost perhaps the best and safest option. but check out the roofs off others local first.
old satellite