Agreed - this not good and frankly unnecessarily difficult.

I have noted earlier commentary on other media along the same lines.

I wonder if you try typing your post code with the first letters in UPPER CASE eg SE23 or SE13 or SE6, whether the field labelled Address may accept that form of input.

Have not tried that yet - but by additionally putting in your full post-code, it may activate a pull down address list to confirm your actual address.

I have seen suggestions that if you do not want LCY to know your actual address, use that of your nearest Railway Station or Post Office.