I would never recommend a mileage run solely for the purpose of getting *G. That's mainly a strategy if you're already flying a lot of Star and are doing so with an airline and fare bucket that would qualify you for A3 Gold with comparative ease. It's a trade-off: you're parking RDM's in a place where you can only get them out via a telephone redemption in exchange for easy lounge access and potentially other minor perks on a *A airline.

Because partner status is never as good as native status, this strategy is most useful to someone who flies 20k-40k/yr on Star. If you're already north of 50k/yr, you're probably better off with native status. If you fly Oneworld (as may be the case with the aforementioned Aussie in the UK), it's no good at all...because Star Gold gets lounge access only in conjunction with an actual Star Alliance flight.

GBP 45 for 6 visits is *probably* a good deal. But if the lounge you're admitted to is one of the unaffiliated lounges staffed by airport contractors, it's worth a lot less than being in the lounge of the airline you're getting ready to fly. I've been in a few of those where I was appreciative of the quiet seat and free coffee, but I was glad I didn't pay for access.