If the GBP:EUR rate changes from its current 1:1.14 to 1:1.3, the pound will have strengthened.
For every £1 that you hold, you can exchange it for €1.30. To acquire £1, you will need to exchange €1.30.
Contrast this with:
If the GBP:EUR rate changes from a theoretical rate of 1:1.3 to 1:1.14, the pound will have weakened.
For every £1 that you hold, you can exchange it for €1.13, which is a decrease from the previous amount of €1.30. To acquire £1, you will now only need to exchange €1.13, as opposed to the previous amount of €1.30.
If you are exchanging Euros for the Pound Sterling, you will be buying Pound Sterling in exchange for Euros.