Rural LTE connection woes

[noggenfogger10]

Hi everyone

So I moved to a rural home just under a year ago and as you can imagine wired broadband is not an option out here so immediately decided to look at options that would work. Mobile internet was my first choice as just under 2km away line of sight is a mast. So, I set about trying to identify the operator and it turned out to be Vodafone, and as I own a mobile through Vodafone I confirmed that this is the mast that my mobile was utilising.

I ordered myself a 4g LTE router and multi-directional aerial and set it all up as well as signing up to Vodafone unlimited max sim. Now the multi-directional aerial didn't cut the mustard as SNR was through the roof at the distance I was dealing with, so I ordered a Poynting 5g directional antenna. Upon setting up and a rough point and shoot I found immediately I was getting crazy speeds over 100Mbps (See photo I attached).

About 4 weeks ago I was struggling to download some files from work so decided to run a speed check to find I barely now push 15-20Mbps at the absolute best. Thinking this maybe overutilisation of the mast I monitored it and these speeds are consistent and now it seems to be a permanent speed. 

My next thought was the Aerial has moved (its well attached so unlikely) but my signal strength was still showing 100%.  I have attached the Signal parameters below. 

See I do not think those are bad and should be getting more than 

Any pointers would be much appreciated

Tim