What sort of off road? For canal towpaths, forestry tracks, etc
suspension isn't needed. Front suspension is worth having for anything
more serious.

Mostly I go along a disused railway (Castleman trailway) that's got a rough
gravel surface, and country park/woodland trails, so I'm thinking that
suspension would probably be not essential.

As suggested by other posters £150 is not enough for a
new bike. At that price point the components just don't work as well,
need more frequent adjustment and wear out faster.

Taking on board what people have said, I am thinking the best solution is a
mountain bike with no suspension. I thank you all for your input, and it's
certainly been very helpful! Also, I think I can up the budget to £200. As
there isn't a tearing hurry to get it, I'll also investigate the free ads
too.

Try looking in a few local bike shops. If you say what area you
live in someone on this group should be able to point you at a
reasonable shop.

I live in the Bournemouth area. I did look in a couple today actually. One
(Bike Lab) didn't seem to stock anything below £500, and one in the local
mall had some, but the only non-suspension mountain bike in stock was a
basic Raleigh that I didn't really like the look of. But the assistant did
give good advice and steered me away from suspension bikes having told her
my use for the bike. A stark difference from Halfords advice that was
basically "biggest price tag".

I'm on holiday from tomorrow, but I'll certainly be looking deeper when I
get back.

Thanks

David