We took the opportunity to tuck into shares of Glasgow-registered The Restaurant Group on Wednesday as we continued our search for long-term investments which can ride out current stock market volatility.

The shares have been a weak market recently on fears over the impact of the higher minimum wage although company boss Danny Breithaupt actually welcomes the move, claiming he can pay for it through operating efficiencies and sees the prospect of happier and more productive staff.

Certainly the Frankie and Benny's and Chiquito chain sees no reason to cut back on its opening programme of around four new outlets a month, largely paid for out of cash flow, and recent figures show fatter margins and continuing like-for-like sales growth.

We have set our usual stop loss figure, 10 per cent below the current share price, which will be used as a sell signal if the shares should go into reverse.

Most of our present share tips managed to move higher in last week's see-saw stock market conditions with three of our four portfolio recording overall gains when we carried out a mid-week review of progress.

The one exception was the 2014 list which slipped back 0.4 per cent after further weakness in social housing and home care group Mears on continuing worries over higher wages for low-paid staff.

The other portfolios recorded average gains of just more than 1.0 per cent although there were a few disappointments with Rentokil recording a small loss in its first week since being added to the 2015 selections and Kingfisher slipping back after disappointing trading news.

Speciality chemicals concern Croda also suffered from nervous selling after recent gains and is in danger of eviction from the 2012 portfolio under the stop-loss stem though most analysts believe the share price is now too low.

But the losers were more than balanced out by a lengthy list of gainers which included Scottish companies Craneware and Smart Metering Systems after encouraging trading news and mental health specialist Cambian following a stockbroker upgrade.