Hi!
Thank you for the background information.
The nearest rescue to you that offers piggy dating (at least cross gender dating) is the RSPCA Bryn-y-Maen in the hills above Colwyn Bay. They don't usually have all that many piggies but it is always worth enquiring. I have travelled there by train in 2017 to adopt my Beryn (Welsh for 'Candytuft' as my hub's family is from North Wales) from them. Sadly there are not many piggy rescues in Wales; and that is putting it rather politely!
Otherwise you may want to make a day trip into the Midlands.
@VickiA - how is the current situation at The Potteries Guinea Pig Rescue in Kidsgrove/Stoke-on-Trent?
Here is our recommended rescues locator:
Recommended Guinea Pig Rescues
It is worth travelling further afield as the key to any successful piggy bond is mutual liking and character compatibility long before age or gender. If you opt for baby boys on spec, then you face the same issues again when they go through their own teenage and are too dominant in outlook themselves. I have often made the experience that what looks perfect on paper can be straight fail when the piggies are face to face.
At least you have the option of looking at both sows or boars for your neutered boy, so he has the widest field to play with. There is a good side to neutering!
Here is more information on companionship for single or fallen-out boars:
A Comprehensive Guide to Guinea Pig Boars
Single Guinea Pigs - Challenges and Responsibilities