Previously rejected because of money

[ApartmentBlock]

My boyfriend is a Grenadian national, so does not need a passport to travel to the UK. I am UK born traveling on a UK passport, but with Grenadian citizenship.

Last time he came, he came a month after me to visit me. He was rejected at the border because he did not have enough money and Border Force misinterpreted my finances when I presented them to them. He was rejected under 4.2 because of lack of funds.

We are now trying to come into the UK together for 5.5 months.

Does this sound like adequate documentation:
- Letter from my mother saying she will sponsor all costs for the whole trip and will provide accommodation for us both
- Photocopy of my mother's passport
- Letter from my mother's bank saying she has maintained a balance of X for 1 year
- Title deeds to my mother's property
- Letter to say someone is taking over our business in Grenada for 6 months
- Tenancy agreement for the people who are renting our property for 6 months
- Title deeds to property in Grenada (in my name)
- Bills sent to property in Grenada (in his name)
- A letter to prove my Grenadian citizenship (do you think it would look better if I also travel on a Grenadian passport? I can if necessary)
- Return flights booked for 5.5 months' time

Many thanks

[ApartmentBlock]

Also we will carry about £4000 in cash through. This is from the sale of a car (£8000), and we are going to buy a cheaper car when back in Grenada with the remainder. Do we have to carry proof of sale of the car etc?

[GMacNab]

People from Grenada need a passport with at least six months validity on it. They do not require a visa.

Grenada - Entry requirements