Posh wellie maker Joules Group PLC (LON:JOUL) sank into the mud this week after an internal error meant its available stock did not match online demand, causing a drop in website sales over the Christmas period.

In a trading update, the retailer said the “misallocation of stock” had resulted in too many of its lines being shipped out to stores and third-party sellers, leaving its website short of items during the festive build-up.

As a result of the mishap, full-year underlying profit before tax is now forecast to come in “significantly” below the £16.7mln that analysts expected.

While Joules said it will be investing extra money to improve its logistics operations (presumably to prevent such a snafu happening again), investors decided to stick the boot in as the stock tumbled 21% to 179p.

The AIM All-Share was mostly flat during the week at 964, while the FTSE 100 was down 0.3% at 7,598.

Holding the small-cap benchmark back was the performance of one of its largest constituents, antibodies specialist Abcam PLC (LON:ABC), which on Friday said rapid investment in its expansion plans meant its profit margin will be at the lower end of guidance for its current year.

Revenues, meanwhile, are set to grow in the 9-10% range. In September, investors were told Abcam expected its turnover to increase by 9-11% to £288-£294mln. The shares were down 7% on Friday at 1,330p.

Miner Trans-Siberian Gold PLC (LON:TSG) saw its shares head underground, plunging 31% to 59p as the mineral resource estimate for its Asacha Gold Mine was slashed to around 312,000 ounces of gold from about 553,052 a year ago following analysis at the project.

The company is now conducting more drilling at the site to try and upgrade the resources, with guidance for the current year expected “shortly”.

IT firm Maintel Holdings plc (LON:MAI) saw around a third of its value wiped away, falling 30% to 284p, as it issued a profit warning and slashed its dividend payout.

Aside from economic uncertainty caused by December’s general election, the company said a protracted delay in the announcement of new public sector procurement frameworks had significantly reduced the number of available bids during 2019, while revenues and earnings had also been hit by the loss of four contracts by two of its partners.

China New Energy Limited (LON:CNEL) lost some momentum as it revealed that the process for listing itself on the Hong Kong Stock Exchange was taking longer than expected, sending the shares down 3.5% to 2.7p.

Meanwhile, shares in eCommerce marketplace builder CloudBuy PLC (LON:CBUY) crashed to Earth, falling 67% to 0.8p, as it proposed delisting from AIM.

Back among the risers, drug developer Midatech Pharma PLC (LON:MTPH) jumped 8% to 3.3p on the back of positive results for its MTD201 cancer treatment.

The analysis revealed that the drug can be delivered via an injection under the skin rather than into the muscle, a fact the firm said was a “key” advantage in paving the way for regulatory approval.

A change at the top sent shares in Providence Resources PLC (LON:PVR) 18% higher to 3.6p as it named Irishman Alan Linn as its new chief executive.

Pawnbroker Ramsdens Holdings PLC (LON:RFX) moved 3.3% higher to 247p after announcing that its pre-tax profits for the year will be “comfortably” ahead of market expectations thanks to strong trading over the Christmas period and higher gold prices.

Shares in MPAC Group PLC (LON:MPAC) soared 29% to 262p as the maker of automated packing solutions said strong order intake in its fourth-quarter led it to upgrade its full-year profit forecasts for the second time in four months.

Elsewhere, internet of things firm Asimilar group PLC (LON:ASLR) got an 86% boost to 46p after raising £6.8 million through the placing of 17 million new shares at 40p, a 15% premium to its close price on Tuesday of 33.8p.