In response to the original question here is the answer I received from FCLWEB:
"If you have been issued with an EASA PPL(A), regulation does not permit you to hold two licences within the same category. If you now wish to convert to a LAPL licence you will be required to surrender your EASA PPL(A).
You will be required to complete the licence conversion requirements and application to convert to a LAPL, including hold a valid Part MED medical certificate at minimum of a LAPL level, a valid SEP or SSEA rating and a valid English language proficiency level. In addition please complete the conversion application form SRG1104 and surrender your PPL(A). The fee to convert to a LAPL is £41.
As an EASA holder, you do not need to complete an additional 10 hours PIC before carrying passengers. However please note that you are not able to add IR or IMC privileges to a LAPL."
Note the fee is only£41! 
The process was pretty slick as well