my cable now is a homemade special with screw on connections what one would you recommend
The green end cables are what VM supplied for self install of hubs, you don't need a powered splitter.
No one needs a powered splitter unless they are adding new long cables to loft rooms etc, if the signal is Sh!te when it comes in as
@Warhammer14 signal is, they don't need a powered splitter, they tell VM they aren't paying another bill until it's sorted.
Buy a HDU and yes, it will make everything work fine - you've just wasted £20 as it should be fine anyway, the fact that you are paying for a substandard service and then using third party hardware to rectify that doesn't make it any better, it's crap now and it's going to continue getting worse.
If you buy a BMW and it doesn't perform as it should, you can get it souped up at cost to yourself to make it do what it's supposed to do anyway or you can tell BMW it's a POS.
the only requirement for a HDU is when adding extra cables, or extending unauthorised VM cables in the house, if using one single cable as the OP is, they are a complete waste of money,
@Warhammer14 gets everything running great with HDU but the incoming signal will remain crap.
When it gets worse
as it will, then he has to call VM, which means the HDU will be unplugged, stuffed in a drawer and forgotten about as it's not required.
It's not required now