If your manual transmission is similar to our North American ones, you should be replacing the manual transmission fluid every 30K miles. If you have overlooked this action, you will be surprised at how well the transmission shifts with fresh fluid.
Folks in the USA recommend Honda OEM MTF or General Motors Manual Transmission Fluid. (Don't know if the latter is available though Vauxhall sources near you?)
If you really think its a binding issue with the shifter linkage, first try spraying a penetrating oil up into the shifter area from underneath. I know that @fishycomics was an advocate of this process. And, I had an '81 Civic that benefited from lubricating the linkages.
Drive the car onto ramps or support it safely with stands!
Folks in the USA recommend Honda OEM MTF or General Motors Manual Transmission Fluid. (Don't know if the latter is available though Vauxhall sources near you?)
If you really think its a binding issue with the shifter linkage, first try spraying a penetrating oil up into the shifter area from underneath. I know that @fishycomics was an advocate of this process. And, I had an '81 Civic that benefited from lubricating the linkages.
Drive the car onto ramps or support it safely with stands!