Ah, not a good way to find the forum, but you're not the first and won't be the last.....
If' you've bent all four valves in the front head you will not need new guides fitting, unless something quite unusual has happened.
You will need new seals, though, and a head gasket of course.
My advice would be to buy a cheap rear head and rob the valves out of it.
You'll need a suitable valve spring compressor, but not all work well- have a look on here, Halfords do one for about £50 or you might be able to borrow one.
You'll need to lap the valves in once fitted, and then re-shim to get the clearances set- while you're doing these, might as well do the rear clearances as well, as you are near enough looking at them.
I'd advise draining the coolant out (it runs out once you take the head off anyway!) but also remove the two rads. It's only some clamps and six bolts, but then gives you so much more access.
Your other option is to part ex your head against one that I or someone else has already prepared- if the replacement head has a set of cams and caps installed you can set the valve clearances (fit the correct shims) while it's off the bike, so you should be able to bolt it straight on.
Factor in the cost of postage both ways as well. It won't be cheap, as it'll need to be a front head.
Lastly, if you have any machining skills, machine a secondhand rear head's blanked off cct adjuster position so that it can be turned into a front one- the castings are the same, with a cct position cast into the head both front and rear- only one is machined, though- machine one and blank the other and you turn front to rear, or vice versa.
If you lived any nearer I'd say I'd collect, but Yorks is a long way to charge you for mileage!
Good luck, with a weekend to spare and doing your homework before you start and it's not difficult.

It's not falling off, it's an upgrade opportunity.