UPDATE:
I pretty much spent all last night emailing a few people...
The print companies all came back stating that £250 is unrealistic. Cheapest was about £370, but most asked for around £700. This doesn't make going with them a realistic proposition...
I just spoke to a rental company, and he charged 1p per (single-sided) page, which would have made the print costs about £400. Not bad, except for the fact that the rental charge was about £85 per month (with 3 months being minimum). So the price would have been around (cost of print+hire cost+paper/staples = 400+(85*3)+115) £770. That makes renting a printer unfeasible, and on par with, if not more expensive than getting the magazine printed with a commercial printing company.
After doing a bit of research on Ebay, these are the printers that have caught my eye at auction - partly because they have booklet makers attached:
Lexmark X945e which is currently sitting at £62 (with 3 days to spare). I anticipate it to go for more than that, but judging what has been shown previously, I might be able to nab it for about £250. Good thing also is that they deliver to London for free. But Lexmark consumables are quite expensive (toner was £146, photoconductor unit was £245), therefore making this printer a very costly long-term proposition.
Canon CLC3200 which is sitting at £34 at present. Delivery would be more though, and I assume it would be around £70 if delivered through a courier. Also, SquareTrade take care of warranties (just under £50 for 2 years - assuming that the printer goes for £200 or less). That would make the whole thing about £150 at present - although I anticipate the printer going for about £150 max, therefore making everything about £270. Having said that, drum units are quite expensive (£250).
Nashuatec DSc328 which is sitting at about £100. Again, delivery would need to be arranged via courier... Also, SquareTrade take care of warranties (just under £50 for 2 years - assuming that the printer goes for £200 or less). This makes the whole thing about £120 plus the cost of the printer - which is making it at least £220 at the moment. I'd say about £250-270 once the auction ends. This is the cheapest, as cartridges cost £40-50 for 19k and the drum unit is less than £60.
Not sure about this
Samsung SCX-6345N, as the owner states that "this printer comes with the stapling and finisher option but I'm not sure if it does what you require for a5". I will have to do some research on this, but it only goes for about BIN £300 including delivery. 2 year warranty option makes it about £350.
If I do buy my own printer - and I am currently looking at the Nashuatec DSc328, I don't think I'll need to be paying more than £300 with all the bells and whistles (including delivery and warranty). The only thing I would need to worry about would be the drum (£80ish) and the toner (£80). With this being the case, I think the average copy will cost me no more than about 10p (including cost of paper and staples). Therefore making the whole print cost about £250 max.
Buying a printer is certainly more cost effective than either renting, or having the work done by an outside print company - both options which would cost me about £700. The purchase of a printer at (less than) £300 - including delivery and warranty - would pretty much pay for itself on the first print run...