I'm not a landlord, so full disclaimer to begin with, but it does read to me (from the linked legislation) that someone without a UK credit history CAN be charged for rent covering multiple months (as long as not exceeding the term of the rental agreement) in a single upfront lump sum.
From experience, when I first moved to the UK, I was explicitly informed that the only reason I wasn't being asked to provide anywhere from 3 to 6 months rent upfront as a single lump sum payment was due to my UK spouse who did have a UK credit history. If I had been looking as a single person newly moved to the UK without UK credit history, I would very likely have been required to pay several months rent upfront.
Q. Can I ask a tenant to pay rent upfront if they don’t have a suitable guarantor or reference checks?
Yes. You could ask a tenant to pay their rent in a lump sum but should consider if this is necessary and affordable for the tenant. You cannot charge any more in an up-front lump sum payment than would have been chargeable over the fixed-term of the tenancy.https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/791273/TFA_Guidance_for_LandlordsAgents.pdfIMO, the above seems clear on this. The way I read it is - as a landlord, you don't HAVE to request rent in a lump sum for tenants without a UK credit history, but you are PERMITTED TO DO SO within reason (e.g. not charging for more than would be ordinarily paid for the length of the tenancy).
For those moving to the UK without a UK credit history, I would recommend to be prepared to pay 6 months rent upfront. You might not have to (which would be fab), but it appears you could be asked to do so.