Ann: Appendix 4C - quarterly, page-54

The R&D tax credit is paid after June 30 in the following tax year so we won't see it in the accounts until FY ending 30 June 2019, by that stage we will know if this investment has been a success.
If they have applied, they will disclose details in the accounting policy note on income tax. I.e. it will probably be a credit to income tax expense.
I think regardless, have a look at the intangibles on the balance sheet and if/how they have grown.
I have seen some companies, from memory ADR, disclose the receipt of the refund as a price sensitive announcement, in that case because the refund was material compared to revenues at the time.
We will soon see.