yes
Yes, you do need your passport.
A passport
No
No
Yes
No
yes, you need a visa as you are not a british passport holder.
No
No. You need a visa to go to England as a Malawian citizen.
An identity card is sufficient for a Romanian citizen.
Only Irish and UK citizens can travel without a passport between the 2 countries
Gibraltar is British territory so you you would not need a passport if you are a British citizen. However if you carrier has any connections elsewhere they may require a passport for boarding.