My dad has the Bush Freesat HD model BFSAT03hd box, the problem he is having is that on initial setup we have 70% signal strength and 40-50% quality. But dependant on which channels he is viewing then the signal totally disappears and he cannot view, namely CBS Action, JML, AlJazeera Eng and a few more plus some of the BBC Hd channels can get a bit twitchy. The dish he is using came with a kit bought from Aldi so its not the usual Sky type dish could this be causing the problems
Any feedback would be much appreciated

The obvious first thing to check is the dish and LNB alignment. Doesn't take much error in either to kill the signal. Provided the dish and LNB are designed to work with the satellites you want to receive and the dish is an appropriate size for where in the world you are then the fact it may not look like the Sky provided kit is irrelevant.

Also check the cable and connectors. If it was self installed did you use proper self amalgamating tape to waterproof the LNB connections or just rely on ordinary insulating tape (or worse no waterproofing at all.

Dish alignment, poor/no waterproofing of connectors and cable damage are the main causes of poor reception - assuming you are using the right kit for the job in the first place.

my money is on dish/lnb alignment/skew. the independent local installer took some time & many tiny adjustments to get my satellite signals as good as they are. you prolly need an analyzer metre too for such tiny changes.

but bad cable (kink etc) or poor F connections will lead to poor results too. some chs on sky/fs are from the neighbouring eutelsat which is weaker than the main Astra group. there needs to b a slight comprimise in alignment to get both.

Thanks for the replys, I will look into all your suggestions and report back