Tortoises can be “incubated to be” a particular gender, but there are no guarantees and you won’t have conclusive evidence until your tort is more mature... possibly 5 years old.
Please ask any questions you have before you spend money. We can save you a heap. Keep in mind that printing a tortoise on a packet seems to double the price of its contents and that not everything sold by pet shops for reptiles/tortoises is in fact suitable. Pet shops seem clueless generally about tortoise care.
I recommend you read the TFO care guides thoroughly and base your setup on them.
They're written by species experts working hard to correct the outdated information widely available on the internet and from pet stores and, sadly, from some breeders and vets too.
Hi and welcome I'm in UK (Wales) too with a Leopard Tortoise.
I took my already large tortoise to a vet 4 years ago when he was about 3 or 4 years old, and was told he was a female.
He has since proudly shown me frequently that he is in fact a male!
So don't expect to know too soon.
Lots of great advice here from people who genuinely only have the best interests of tortoises at heart - not profit, so read the caresheets and ask as many questions as you need there is always someone around to help.