Hi Chumperchops
Contary to some of the possible suggestions I would think carefully before changing your electricity tariff, as you indicated your water boiler is still on the E7.
A single rate tariff might sound cheaper but the low option of E7 is usually over 50% cheaper than the day unit price of a single rate meter. Basically as a general rule of thumb, despite companies offering either a No Standing Charge (where for E7 you have two day rate prices, a really high one, than a lower one, then your night rate price, which should as said be over 50% cheaper than the lower day one, or a standing charge, so one price for your day units, one price for your night units(again cheaper) and a daily rate. IF YOU use more than 18% of your usage on your low rate, then changing to a single rate meter will be more expensive.
Basically this boils down too the fact of the cheaper night rate you are gaining because of the unit price compared to your day time usage.
Also for a change in tariff you usually have to have the meter changed. All the companies either want to sign up single rate customers or E7 most cant have multirate meters. So as you are with Scottish Gas this leads me to believe you have changed before. Despite their recent reductions, they are not the cheapest for electricity, so think about changing supplier.
Ask ScottishGas for your current annual usage in Kilowatt Hours, for your day & night, or if they wont give it to you (which they should) ask them for historical meter readings which are roughly a year apart. Then work it out. Basically by putting this into some of the comparison websites, and selecting electricity only supply, you should get some better results, without the possibility of taking a day off work to wait for an engineer to arrive that probably wont, and you have to wait again. Also as an afterthought, if there is nothing wrong with the meter, i.e timeswitch etc (for E7) i think Scottish Gas charge for meter changes where its purely cosmetic tariff change.
Let us know how you get on
Cheers