our little company Poseidon not for so long, page-3

I understand that refurbishment works are supposed to take 9-12 months. But what about the planning stage? Do we not need to get a/some consultant/s on board to develop a brief of what refurbishment work is required? Then, don't we need to prepare tender documents that will go out to market or to a few selected contractors for them to price? Then, we will have to assess the bids and allocate the contract. Then, there will be a mobilisation period before works start. Assuming all this is required, this is what it should look like. Appointing consultants to develop project brief - say 3 to 4 months. Tender preparation and bid acceptance - 2 months. Refurbishment works - 12 months.

August 2019 + 4 months (planning stage) = December 2019
Lose 1 month as people normally take their holidays during the December / January period.
Tender process to award of contract = February 2020 + 2 months = April 2020
Refurbishment works = April 2020 + 12 months = April 2021 (almost two years from now)

Can anyone tell me whether the planning and tender process is required or whether Management simply need to wait for a period (say 3 months) and can award the tender to someone straightaway at the start of November this year and they can mobilise on site and start the refurbishment works in November itself which means we have a worst case of November 2020 for start of production (1 year and 3 months from now)?

Thanks