The market value of it, without calibration and certification, is going to be somewhere between £175-275 I'm afraid, and that is selling to someone actively looking for one. With a recent service, calibration and Nist certificate though, it may well be worth £500 to the right person that has a requirement to satisfy. Assuming of course that there is nothing more than the odd mark on the casing and it comes with the manual intact, cover, probe pouch etc. Personally I would split the probes, they will likely net you £100 on their own if they are in good condition and should sell easily. The scope will probably still fetch around the £150-175 mark without them, but will take a bit longer to sell. Despite costing literally thousands when new, these things depreciate faster than old rusty cars, 5 years down the line and it's probably worth more in tax offset by scrapping it, than it is by selling it. I sold my old Tek 2465 with DMM, not calibrated but in good condition with a probe and manual, about 2 years ago, for a measly £260, despite having paid £1500 for it a few years beforehand with a calibration cert. I practically gave my little Topward beater away 4 months ago after I had paid the ebay fees and shipping, insurance etc. It's a sad fact, but a fact none the less, it's worth more to you if you have a need for it, than it is selling it. Unless I had a very good reason to have an analog 'scope now, I wouldn't even consider the investment