There is a new scheme for the public to request that their local WHSmith or other newsagent stocks copies of magazines they want. So if your local Smiths doesn't have LXF and you would like it to (or you can't find in Maidenhead), you can place an individual order.
There is a form to hand in to the newsagents in the back of er, Linux Format, but that won't be much help to you if you can't find it in the shops! So you could try asking if WHSmiths has a Just Ask form, and go from there.
Hope this is helpful