I changed from the omni-directional Status to the directional one, and it performs very much better.
I used the longer tube one that has a lower support fitted against the wardrobe wall.
I also worried a lot before I did it but its easy, and doing it myself I know its well sealed.
The new aerial does not require any sealant it comes with a special soft foam sealing washer.
I used the plate Status sell to cover holes [cable and screws]left by removing the old unit and this did need mastic sealant.
My conversion was complicated by the new unit needing to come through the roof where that plate was but not through its centre.
With the existing one removed I drilled with a fine piece of piano wire in a hand brace a hole up from inside the wardrobe after marking exactly where it needed to be to suit the lower clamp. I then went up a ladder to inspect the roof and find the hole. I found that I could find a location where the plate covered the original holes and could accommodate the mounting collar of the new unit. I then fixed it down, sealing with a generous covering of a compliant non setting sealant. Back inside and drilled up again so the hole came through. Then using the requisite saw type hole cutter I bored the hole first halfway through from below, then back up the ladder to bore from the top. Then assembled all the bits as per the instructions.