Just a reminder that London is not 'England' as far as transport is concerned. You may have seen on the news that single bus fares in England are going to rise to £3. This doesn't apply to London. Bus fares in London are currently £1.75 (and that includes free changes within an hour of tapping in).
You also have two choices for the bus, you can use the handy stop outside the Premier Inn or walk through the covered elevated walkway to T4. Obviously the one opposite the PI is handier for the PI, it's also handier for the Hilton but I'm not sure about the HIX/CP. However is it's raining worse than Manchester and you don't want to spend even a few minutes outside then the route via the airport is less exposed.
That said, despite good intentions, I often end up just taking Uber. The PI can be such good value that the cost of hotel + Uber still works out cheaper than the hotel alone in most cases.