You might be out of luck.
The Dvdreviewer website seems to have morphed into myReviewer.com (and imported their content). The only hack given for your DVD player suggests that its remote control doesn't have the necessary capability and that you need to use a universal remote control instead. However the two models mentioned are both out of production and not available through either Amazon or eBay:
https://www.myreviewer.com/Site/ForumSearch/dvp-sr760h
It might still be worth trying the instructions under 'Once your remote control is programmed' anyway, either with your DVD player's own remote control or with any other universal remote control you use.
The manufacturers of DVD players are contractually obliged to ensure that they can only be used on one region and it's now getting far harder than it used to be to hack them into multi-region capability.
It might be simplest to fork out thirty quid for another DVD player:
Amazon.co.uk User Recommendation