It's not post Soviet-Afghan, but it is post Vietnam.

During the 1982 Falklands War records indicate that British forces did fix bayonets during at least two actions that I can find sources for. Firstly, The Falkands War by Martin Middlebrook notes bayonet use at the Battle of Mount Longdon.

From Corporal Ian Bailey 3rd Parachute Regiment:

For some reason, most of them fixed bayonets; I put mine in and looked around to find all the others were putting theirs on too.

From Colour-Sergeant Brian Faulkner, 3rd Parachute Regiment:

Some of the Argie wounded had been wounded by phosphorous grenades - severe, deep, burn wounds, very painful. They screamed, were very upset. One or two had bayonet wounds - very unusual in a modern battle - and some were even physically mauled, literally from hand-to-to hand fighting with rifle butts or anything that had come to hand.

Also Wikipedia mentions bayonet use during the Battle of Mount Tumbledown and following the sources there you can find the citation for the Military Cross awarded to (then) Major John Kiszely:

he killed two enemy with his rifle and a third with his bayonet.

https://www.thegazette.co.uk/London/issue/49134/supplement/12847

Hi OP and potential respondents: just a reminder of few subreddit rules.

• No current events. OP, your time period is post-Soviet Afghan War, i.e. >1989, whereas this sub's 20-year cutoff is <1997, which leaves only 9 years. If you're interested in more recent events, do consider x-posting to a military or weapons sub.

• No personal anecdotes. Sorry soldiers!

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Thanks all!