The four most common solutions, in no particular order, would be:
1) Use Component Out on the DVD player if it and the TV have it
2) Buy a SCART switcher box. [Basic ones have to be switched manually, so that means getting up to press a button on the device when swapping between sources.]
3) Buy a SCART to HDMI convertor. [Sounds simple, but the catch is that unless you spend a chunk of cash a lot of these only work with a very basic quality of video signal called 'composite' via the SCART connection. This isn't as good as RGB via SCART. You might as well hook up the yellow composite feed between the player and TV. It'll do the same thing and save you some cash.]
4) Update the player to something with HDMI. A second-hand Blu-ray player from the local classifieds might cost under £20. This would be my recommended choice.
If this or any other reply was helpful to you, then please do the decent thing and click the T-H-A-N-K-S button. It appears when you hover the mouse pointer near the Quote Multi-quote buttons. This is the proper way to show your thanks for the time and help someone gave you.