Are these benefits in kind taxable even at Christmas?

Variations on the following enquiry may appear on business and tax forums at this time of year:

I am becoming increasingly concerned about my potential liability to UK taxes. I am non-domiciled and non-resident (I think) in the UK – no permanent home here – but each year I work temporarily in the UK for a short period. 

The work is unpaid, but I do receive millions of unsolicited (but habitual) benefits in kind such as glasses of port, mince pies and the like. I am becoming concerned that I have not declared these to HMRC in the past.  The aggregate value of these gifts and benefits would be substantial but I have no idea how to value them all. Should I have done so and how would the value of is there an annual tax liability to be paid on these gifts and benefits?  

If I am subject to tax then I would want to offset my travel expenses and the cost of my vehicle and support staff - none of whom are on my payroll. Can I also offset the cost of customer gifts? (Few of them are food and drink but none contain my business logo as such). 

I like to think I'm being nice, but am I naughty? Do I need tax advice or can I safely continue to ignore my self assessment tax filing obligations?  

The usual pseudonym used by the author is "S. Claus". I wonder........

The 6 worst things that happen to auditors

1. Getting in early only to find the manager who's got all the answers is not in today.
2. Being asked to process a whole shed-load of material adjustments 1 hour before the audit is supposed to finish.
3. Realising that the 'we-could-finish-a-week-early-and-have-a-jolly' budget has disappeared into thin air.
4. Being shoved into a cold, pokey, little room in the basement with no windows, mobile phone reception, printer or copier, miles away from where all the people you need to speak to work and 12 floors from the nearest decent snacks vending machine.
5. Having to ask the difficult finance manager at a client the same questions you know they get frustrated having to answer every year as they explain that nothing has changed.
6. Finding out that your favourite prestigious audit client has gone bust and your audit partner has gone missing.

What else do clients say when you tell them how much tax to pay?

In conversation with an accountant recently he told me he'd lost track of how many clients say things like:

Are you on some sort of xxxxing commission for the taxman?!

or

Do you get some sort of sadistic pleasure from the amount of tax you're telling me I owe?

Any more?
(Please keep them clean!)