The UK House of Commons Code of Conduct is very clear about what gifts must be disclosed. The gift received by Nigel Farage does NOT require disclosure. The relevant rule is cited below:
42. Members should not register under this category:
a) Benefits which could not reasonably be thought by others to be related to membership of the House or to the Member’s parliamentary or political activities, for example purely personal gifts or benefits from partners or family members, or loans or mortgage arrangements on commercial terms. However, both the possible motive of the giver and the use to which the gift is to be put should be considered. If there is any doubt, the benefit should be registered;
Nigel Farage at the time he received his gift was not a member of parliament, nor did he intend becoming an MP. Thus, no-one could reasonably think this gift was anything other than personal in nature. Such personal gifts are expressly excluded and SHOULD NOT be reported.
Mr Farage is being pilloried for following the express rules.
Clearly, there is an attempt underway to neuter him politically. With a delegitimised Andy Burnham about to become PM, a General Election may be about to be called and they want Farage pushed under. His move to resign and force a by-election in his constituency is a genius move as he has now been elevated to top of the news cycle, effectively making Burnham look weak and useless.
https://publications.parliament.uk/pa/cm201516/cmcode/1076/1076.pdf