Certainty in an uncertain world

We are exploring an interesting deal in West London. The reason it’s of interest is not architectural, it’s the numbers. More specifically the certainty of the numbers.
The property is a mixed use building, a shop and uppers. The uppers consist of two flats, both producing a decent rental, due to the location.
There is a separate office building which is currently used as an office. This can be converted into residential, under PD. This means this can be done without the need for planning, thus removing the uncertainty associated with planning permission.
The commercial itself can be converted into residential under the same rules; thereby negating the risk associated with obtaining planning permission.
The reason why this is a good deal is the risk associated with obtaining planning in both these scenarios has been mitigated.
This of course does not mean the deal is without risk. You still have interest rates, build costs, and market conditions etc to contend with.
In a project, gaining planning permission is usually a big variable, therefore mitigating this gives much certainty to the project.
Not only is it defined but the time period within which the council has to grant the permission is also laid out in stone – 56 days is the rule. On a previous development the permission was granted bang on the 56th day. Otherwise, my understanding is you have the permission by default.
The first option for the commercial element would be to keep it as commercial. This removes the need for any refurbishment, or only a minimal level in order to appeal to the prospective tenant.
The second option is to consider splitting the premises into smaller units, this would enable the prospective unit to fall below the threshold of paying business rates. This then becomes very appealing for any tenants. Under the new Class E the usage of a commercial premises is not only variegated but one can switch between the two, it is not locked. This means it can even operate as an office during the day and be a café in the evenings. There exists much flexibility with this class.
There is of course always the potential to create residential. This will require development. In comparison, commercial rental is more favourable, as you don’t have voids, no maintenance, and the tenant is responsible for the upkeep of the external, at least partially.
However, if the goal is to extract money then the route to go would be residential. This would give the greatest uplift in values, which would mean this can be extracted on completion by way of refinance.
 The cost of the deal is £2M, and requires an investment of £1M. It is income producing from day one, and one can expect to receive a large chunk of the £1M back at completion; and have an asset which is income producing in a strong location, where values are only expected to increase.