@Rob8430 I have spent a lot of time trying to find out when a guest gets tenants rights in the UK. The best I have come up with is they may do after 6 months or so but this is only based on an insurance company definition. More important seems to be that things like including heating, lighting, TV licence etc must be included in the nightly rent. If the guest is responsible for (any of?) these then they may be considered a tenant.
Finally are you operating as a Furnished Holiday Let? If so any stays over 30 (31?) do not count towards the 105 day requirement.
If there is a UK lawyer out there that can point me to the legislation I would love to hear from them.
And now I see your place is in France - So the above is irrelevant!