With one exception (see below) I don't see anything illegal in what
Kopterman has proposed.
Air Navigation Order 2005
160. Public transport and aerial work—exceptions—cost sharing
(1) ............... a flight shall be deemed to be a private flight if the only valuable consideration given or promised in respect of the flight or the purpose of the flight falls within paragraph (2) and the the criteria in paragraph (3) are satisfied.
(2) Valuable consideration falls within this paragraph if it is —
(a) n/a
(b) n/a
(c) is a contribution to the direct costs of the flight otherwise payable by the pilot in command;
or falls within any two or all three sub-paragraphs.
(3) The criteria in this paragraph are satisfied if—
(a) no more than 4 persons (including the pilot) are carried;
(b) the proportion which the contribution referred to in paragraph (2)(c) bears to the direct costs shall not exceed the proportion which the number of persons carried on the flight (excluding the pilot) bears to the number of persons carried (including the pilot);
(c) no information shall have been published or advertised prior to the commencement of the flight other than, in the case of an aircraft operated by a flying club, advertising wholly within the premises of such a flying club in which case all the persons carried on such a flight who are aged 18 years or over shall be members of that flying club; and
(d) n/a
He is not publishing information or advertising a flight. He could only do that under the conditions specified in (c) above. He is looking for people to cost share. The
Private Flying forum has had a 'spare seat' thread (some cost-sharing, some free) for some time without, as far as I know, any problems.
I'm mystified by the almost aggressive tone of some posters here. Those who see no advantage for them won't take up the suggestion; others may. I suspect the idea may be more attractive to those without a PPL(H). He may or may not find anyone taking up his suggestion, but I don't understand the criticism of him for trying.
Kopterman You can
not "fly with another ppl(h), say 50:50 split (in both terms of cost & time flown) and be allowed to log the whole flight time as PIC/P1 time." You have either misunderstood your CFI or been ill advised. You are only entitled to log the time you fly.
(Edit)
Whirlygig Surely Kopter's response to the PPL(A) who 'wanted a go' as part of the cost share was entirely proper?
FL