Registration for an overseas buyer

Hi all
I'm looking for guidance on my situation. I'm British, but I live overseas.

Finding a UK conveyancer that can cope with my ID check is proving difficult. They all seem to use an online service which crashes as soon as I enter a non-UK post code. 

The purchase is extremely straightforward (no mortgage, freehold, searches already done) so I'm considering DIY, but want to understand how and when I deal with the ID aspect.

Many thanks for any guidance

Hi Roy - see PG 67 section 8.6 for guidance 
Practice guide 67: evidence of identity - GOV.UK