After the recent mixed performance from the High St, all eyes will be on Marks &amp; Spencer on Wednesday as it reports its second-quarter sales.<br /><br />The company&rsquo;s shares have added 16 per cent over the past three months, and a less-than-positive update could lead to a bit of profit taking on the day. <br />Societe Generale has forecast a 2.6 per cent decline in like-for-like sales in general merchandise and a 0.5 per cent drop on a like-for-like basis in Food.