rear shock absorbers

i have been experiencing problems getting the correct shocks for the back of my t5 it is a 2000 w reg last of the old shape but the motor factors have sent out two types of shocker both gas type but neither seems right the existing shockers are big thick topped with aslight taper at the top the replacement ones ive been sent have a flat top thus dont fit the whole properly any chance anyone knows what im talking about is there a different option and where from and how much i am reluctant to order anything till im sure its what i need

Are you sure they're not auto levelling? Like these:

looks like it 

that is what im looking for a good picture of what i want before i buy