My name is ***** ***** I have been a solicitor for more than 35 years.
I am afraid that you have no right to return to the property at this stage
So fas as the cars are concerned if they were gifts to her then I am afraid that there is no action you can take to recover them or the money you spent on them.
The money that you spend on simply decorating the property is also lost I am afraid.
However the money that you spent on structural improvements to the property such as the Kitchen and the bathroom may give you a potential claim on her property.
Not a massive claim - but one which reflects the increase in the value of the property which relates to the new Kitchen and bathroom.
This is a matter that you should try and discuss with her using Family Mediation
If that fails then you may be able to apply to the courts using s14 of the Trusts of Land and Appointment of Trustees Act.
You can read more here
I hope that this is of assistance - please ask if you need further details